Real-time scalable virtual session and network analytics

ABSTRACT

Provided herein are systems and methods for providing insights or metrics in connection with provisioning applications and/or desktop sessions to end-users. Network devices (e.g., appliances, intermediary devices, gateways, proxy devices or middle-boxes) can gather insights such as network-level statistics. Additional insights (e.g., metadata and metrics) associated with virtual applications and virtual desktops can be gathered to provide administrators with comprehensive end-to-end real-time and/or historical reports of performance and end-user experience (UX) insights. Insights relating to an application or desktop session can be used to determine and/or improve the overall health of the infrastructure of the session, Citrix Virtual Apps and Desktops, the applications (e.g., remote desktop application) being delivered using the infrastructure, and/or the corresponding user experience.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 62/767,947, titled “REAL-TIMESCALABLE VIRTUAL SESSION AND NETWORK ANALYTICS,” filed Nov. 15, 2018,which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present application generally relates to communicating insights suchas application and/or desktop performance and end-user experienceinsights, including but not limited to systems and methods for real-timescalable virtual session and network analytics.

BACKGROUND

In a network computing environment, insights and metrics aboutapplication and/or desktop performance, and on end-user experience, canbe used to determine the health of the network computing environmentsuch as the associated application or desktop delivery platform.

BRIEF SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features oressential features, nor is it intended to limit the scope of the claimsincluded herewith.

Described herein are systems and methods for providing insights ormetrics in connection with provisioning applications and/or desktopsessions to end-users. Network devices (e.g., appliances, intermediarydevices, gateways, proxy devices or middle-boxes) such as Citrix Gatewayand Citrix software-defined wide area network (SD-WAN) devices cangather insights such as network-level statistics. Additional insights(e.g., metadata and metrics) associated with virtual applications andvirtual desktops can be gathered to provide administrators withcomprehensive end-to-end real-time and/or historical reports ofperformance and end-user experience (UX) insights. Insights relating toan application or desktop session can be used to determine and/orimprove the overall health of the infrastructure of the session (e.g.,XenApp/XenDesktop infrastructure), the applications (e.g., MicrosoftOffice applications, remote desktop application) being delivered usingthe infrastructure, and/or the corresponding user experience. Theinsights can be combined with other network-health analysis performed bynetwork devices, and/or processed by the network devices (e.g. CitrixGateway or Citrix SD-WAN). In addition, such collective insights may beprovided to a management and triaging utility (e.g. Citrix Director), amanagement analytics service, or a third party collector tool. Thecollective insights and/or these tools can allow administrators to viewand analyze real-time client, host and network latency metrics,historical reports and/or end-to-end performance data, and can allow theadministrators to troubleshoot performance and network issues. However,to obtain the insights, the network devices may have to perform deepparsing of virtualization protocols such as Citrix independent computingarchitecture (ICA) along with some or all virtual channels (VCs), whichcan demand or entail knowledge of all underlying protocol details, andcan be resource intensive.

To address these and other challenges, the present disclosure providesembodiments of methods and systems for providing or delivering insightsof a virtual session to a network device in a real-time, scalable and/orextensible manner. In some embodiments, a separate or independent VC(sometimes referred to as an App Flow VC, app flow VC or insights VC)can be established across or between a client-side agent (e.g., desktopvirtualization client), network device(s) and a server-side agent (e.g.,virtual delivery agent (VDA)) for the transmission of insights (e.g.,virtualization session insights). The App Flow VC can be negotiatedbetween these entities (e.g., between the desktop virtualization client,network appliances and VDA). The App Flow VC can facilitate scalable andextensible processing of insights.

Some embodiments of the present methods and system provide or supportstate transition of App Flow insights or metrics (sometimes referred toas app flow or insights) during network device failover (e.g.,high-availability failover). Certain embodiments of the present methodsand system provide or support efficient identification andprioritization of MSI HDX streams. Some embodiments of the presentmethods and system provide or support layer 7 (L7, application layer)latency calculation and communication independent of host processingtime. Some embodiments of the present methods and system provide orsupport L7 latency calculation and communication between multiplenetwork devices.

At least one aspect of the present disclosure is directed to systems,methods, and non-transitory computer readable media for negotiation andestablishment of independent app flow virtual channels. A firstcomputing device may send a request message to a second computing devicevia an intermediary device. The request message may be indicative of acapability of the first computing device to support an insights virtualchannel (VC) between the first computing device and the second computingdevice. The first computing device may receive, responsive to therequest message, a response message. The response message may include anindication of a capability of the second computing device and anindication of a capability of the intermediary device, to support theinsights VC. The first computing device may establish, according to thecapabilities of the first computing device, the second computing deviceand the intermediary device, the insights VC to communicate insights foruse by at least one of the first computing device, the second computingdevice or the intermediary device.

In some embodiments, the request message may include a highest of aplurality of versions of a protocol that the first computing device cansupport to use the insights VC to communicate the insights. In someembodiments, the first computing device may establish the insights VCaccording to a highest of a plurality of versions of a protocol that issupported across the first computing device, the second computing deviceand the intermediary device to use the insights VC.

In some embodiments, the first computing device may establish aplurality of VCs between the first computing device and the secondcomputing device, separate from the insights VC. The plurality of VCsmay be at least one of interleaved with each other or configured tocarry compressed data. The insights VC may be at least one ofnon-interleaved with any of the plurality of VCs, or configured to carryuncompressed data.

In some embodiments, the response message may include informationassociating an identifier of a protocol for communicating data using theinsights VC, with an identifier of the insights VC or a component of thefirst computing device. In some embodiments, the first computing devicemay identify or access the insights VC from among a plurality of VCs,using the information.

In some embodiments, the first computing device may access, via theinsights VC, insights from at least one of the second computing deviceor the intermediary device. In some embodiments, the insights from theintermediary device may include analytics about a network of theintermediary device.

At least one aspect of the present disclosure is directed to systems,methods, and non-transitory computer readable media for state transitionof app flow metrics during network appliance failover. A first devicemay be intermediary between a first computing device and a secondcomputing device. The first device may determine that an insightsvirtual channel (VC) established between the first computing device andthe second computing device, is re-routed to the first device from asecond device intermediary between the first computing device and thesecond computing device. The first device may receive protocol state ofthe insights VC. The protocol state may include information associating(i) an identifier of a protocol for communicating insights using theinsights VC, with (ii) an identifier of the insights VC or a componentof the first computing device. The first device may access, using thereceived protocol state, the insights communicated via the insights VC,that are from at least one of the first computing device or the secondcomputing device.

In some embodiments, the first device may receive the protocol state ofthe insights VC from a shared storage. The protocol state may be savedby the second device in the shared storage. In some embodiments, theprotocol state of the insights VC may include capabilities negotiatedacross the first computing device, the second computing device and thesecond device, to support communicating the insights via the insightsVC. In some embodiments, the protocol state of the insights VC mayinclude at least one of a protocol name of the insights VC, informationabout event of the insights VC, and data points of the insights VC.

In some embodiments, the device may receive the protocol state of theinsights VC by identifying the protocol state using a protocol-levelidentifier. In some embodiments, the device may receive the protocolstate of the insights VC by accessing the identified protocol state fromthe shared storage. In some embodiments, the protocol state of theinsights VC may include at least one of an encryption method, anencryption key, or a last encrypted byte.

In some embodiments, the first device may re-synchronize, at a commongateway protocol level, packets transmitted or received via the insightsVC. In some embodiments, the first device may initialize orre-initialize using a tunneling protocol. In some embodiments, the firstdevice may receive the protocol state of the insights VC from a VC agentexecuting at the first computing device or the second computing device.In some embodiments, the protocol state of the insights VC may includecapabilities negotiated across the first computing device, the secondcomputing device and the second device, to support communicating theinsights via the insights VC.

At least one aspect of the present disclosure is directed to systems,methods, and non-transitory computer readable media for identificationand prioritization of Multi-stream ICA (MSI) HDX streams. A first devicemay establish a plurality of data streams between the first device and asecond device. Each of the data streams may include at least one virtualchannel (VC), wherein a first data stream of the plurality of datastreams includes an insights VC. The first device may determine, foreach corresponding data stream of the plurality of data streams, anidentifier and a priority of the corresponding data stream. The firstdevice may send, for each corresponding data stream of the plurality ofdata streams, information regarding the identifier and the priority ofthe corresponding data stream, in the corresponding data stream, to beaccessed by a computing device intermediary between the first device andthe second device.

In some embodiments, the first device may send, in the correspondingdata stream, the information including a globally unique identifier of asession of the plurality of data streams. In some embodiments, the firstdevice may send, in the corresponding data stream, the informationincluding a type of the corresponding data stream. In some embodiments,the type of the corresponding data stream may correspond to a primarydata stream or a secondary data stream.

In some embodiments, the first device may determine, for eachcorresponding data stream of the plurality of data streams, an updatedpriority of the corresponding data stream. In some embodiments, thefirst device may send, for each corresponding data stream of theplurality of data streams, information regarding the identifier and theupdated priority of the corresponding data stream, in the correspondingdata stream.

In some embodiments, the first device may communicate data in theplurality of data streams via a single port to server or a clientdevice. In some embodiments, the first device may send the informationresponsive to establishing one of the plurality of data streams.

At least one aspect of the present disclosure is directed to systems,methods, and non-transitory computer readable media for applicationlayer (L7) calculation and communication independent of server hostprocessing time. A device intermediary between a client device and aserver may incorporate a token to a first packet at a time T1. Thedevice may cause the server to receive the token in the first packet ata time T2, and to determine a duration D for generating a payloadrelative to T2. The device may receive a second packet with the payloadat a time T3. The device may determine a round-trip network timeaccording to T3−T1−D.

In some embodiments, the device may receive the first packet from theclient device. In some embodiments, the device may record the time T1.In some embodiments, the device may cause a driver of the server toreceive the token in the first packet at the time T2. In someembodiments, the device may cause an application of the server togenerate the payload responsive to the first packet. In someembodiments, the device may cause the driver of the server to receivethe payload at a time T2 a, wherein D=T2 a−T2.

In some embodiments, the payload may be in Javascript object notation(JSON) format. In some embodiments, the device may receive the secondpacket in an insights virtual channel (VC) established between theclient device and the server. In some embodiments, the insights VC maybe non-interleaved with other VCs established between the client deviceand the server, and the payload in the second packet comprisesuncompressed data.

In some embodiments, the device may incorporate an identification of thedevice in the first packet. In some embodiments, the device maydetermine the round-trip network time if the second packet includes theidentification of the device. In some embodiments, the device mayreceive a third packet from the server. In some embodiments, the devicemay bypass a determination of the round-trip network time according tothe third packet, if the identification of the device is absent in thethird packet.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Objects, aspects, features, and advantages of embodiments disclosedherein will become more fully apparent from the following detaileddescription, the appended claims, and the accompanying drawing figuresin which like reference numerals identify similar or identical elements.Reference numerals that are introduced in the specification inassociation with a drawing figure may be repeated in one or moresubsequent figures without additional description in the specificationin order to provide context for other features, and not every elementmay be labeled in every figure. The drawing figures are not necessarilyto scale, emphasis instead being placed upon illustrating embodiments,principles and concepts. The drawings are not intended to limit thescope of the claims included herewith.

FIG. 1A is a block diagram of a network computing system, in accordancewith an illustrative embodiment;

FIG. 1B is a block diagram of a network computing system for deliveringa computing environment from a server to a client via an appliance, inaccordance with an illustrative embodiment;

FIG. 1C is a block diagram of a computing device, in accordance with anillustrative embodiment;

FIG. 2 is a block diagram of an appliance for processing communicationsbetween a client and a server, in accordance with an illustrativeembodiment;

FIG. 3 is a block diagram of a virtualization environment, in accordancewith an illustrative embodiment;

FIG. 4 is a block diagram of a cluster system, in accordance with anillustrative embodiment;

FIG. 5 is a block diagram of an embodiment of a system for providing orusing a virtual channel to provide insights, according to anillustrative embodiment;

FIG. 6 is a diagram of an embodiment of a system and method forproviding or using a virtual channel to provide insights, according toan illustrative embodiment;

FIG. 7 is a block diagram of an embodiment of a system for App Flow datapoints collection and transmission, according to an illustrativeembodiment;

FIGS. 8-10 provide example charts comprising test results comparingimplementations with and without using an App Flow virtual channel forinsights, according to an illustrative embodiment;

FIG. 11 is a flow diagram of a method of establishing independentapplication flow virtual channels, according to illustrativeembodiments;

FIG. 12 is a block diagram of a system of transitioning application flowmetrics during appliance failover, according to illustrativeembodiments;

FIG. 13 is a flow diagram of a method of transitioning application flowmetrics during appliance failover, according to illustrativeembodiments;

FIG. 14 is a block diagram of an embodiment of a system for providingmulti-stream ICA (MSI) between client-side and server-side networkdevices, according to illustrative embodiments;

FIG. 15 is a flow diagram of a method of prioritizing data streams forvirtual channels, according to illustrative embodiments;

FIG. 16 is a diagram illustrating a method for calculating latencyindependent of server processing time, according to illustrativeembodiments; and

FIG. 17 is a flow diagram of a method of calculating latency inapplication layer (L7) communications independent of host serverprocessing time, according to illustrative embodiments.

The features and advantages of the present solution will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, in which like reference charactersidentify corresponding elements throughout. In the drawings, likereference numbers generally indicate identical, functionally similar,and/or structurally similar elements.

DETAILED DESCRIPTION

For purposes of reading the description of the various embodimentsbelow, the following descriptions of the sections of the specificationand their respective contents may be helpful:

Section A describes a network environment and computing environmentwhich may be useful for practicing embodiments described herein;

Section B describes embodiments of systems and methods for delivering acomputing environment to a remote user;

Section C describes embodiments of systems and methods for virtualizingan application delivery controller;

Section D describes embodiments of systems and methods for providing aclustered appliance architecture environment; and

Section E describes embodiments of systems and methods of providing orusing a virtual channel to provide insights.

A. Network and Computing Environment

Referring to FIG. 1A, an illustrative network environment 100 isdepicted. Network environment 100 may include one or more clients102(1)-102(n) (also generally referred to as local machine(s) 102 orclient(s) 102) in communication with one or more servers 106(1)-106(n)(also generally referred to as remote machine(s) 106 or server(s) 106)via one or more networks 104(1)-104 n (generally referred to asnetwork(s) 104). In some embodiments, a client 102 may communicate witha server 106 via one or more appliances 200(1)-200 n (generally referredto as appliance(s) 200 or gateway(s) 200).

Although the embodiment shown in FIG. 1A shows one or more networks 104between clients 102 and servers 106, in other embodiments, clients 102and servers 106 may be on the same network 104. The various networks 104may be the same type of network or different types of networks. Forexample, in some embodiments, network 104(1) may be a private networksuch as a local area network (LAN) or a company Intranet, while network104(2) and/or network 104(n) may be a public network, such as a widearea network (WAN) or the Internet. In other embodiments, both network104(1) and network 104(n) may be private networks. Networks 104 mayemploy one or more types of physical networks and/or network topologies,such as wired and/or wireless networks, and may employ one or morecommunication transport protocols, such as transmission control protocol(TCP), internet protocol (IP), user datagram protocol (UDP) or othersimilar protocols.

As shown in FIG. 1A, one or more appliances 200 may be located atvarious points or in various communication paths of network environment100. For example, appliance 200 may be deployed between two networks104(1) and 104(2), and appliances 200 may communicate with one anotherto work in conjunction to, for example, accelerate network trafficbetween clients 102 and servers 106. In other embodiments, the appliance200 may be located on a network 104. For example, appliance 200 may beimplemented as part of one of clients 102 and/or servers 106. In anembodiment, appliance 200 may be implemented as a network device such asNetScaler® products sold by Citrix Systems, Inc. of Fort Lauderdale,Fla.

As shown in FIG. 1A, one or more servers 106 may operate as a serverfarm 38. Servers 106 of server farm 38 may be logically grouped, and mayeither be geographically co-located (e.g., on premises) orgeographically dispersed (e.g., cloud based) from clients 102 and/orother servers 106. In an embodiment, server farm 38 executes one or moreapplications on behalf of one or more of clients 102 (e.g., as anapplication server), although other uses are possible, such as a fileserver, gateway server, proxy server, or other similar server uses.Clients 102 may seek access to hosted applications on servers 106.

As shown in FIG. 1A, in some embodiments, appliances 200 may include, bereplaced by, or be in communication with, one or more additionalappliances, such as WAN optimization appliances 205(1)-205(n), referredto generally as WAN optimization appliance(s) 205. For example, WANoptimization appliance 205 may accelerate, cache, compress or otherwiseoptimize or improve performance, operation, flow control, or quality ofservice of network traffic, such as traffic to and/or from a WANconnection, such as optimizing Wide Area File Services (WAFS),accelerating Server Message Block (SMB) or Common Internet File System(CIFS). In some embodiments, appliance 205 may be a performanceenhancing proxy or a WAN optimization controller. In one embodiment,appliance 205 may be implemented as CloudBridge® products sold by CitrixSystems, Inc. of Fort Lauderdale, Fla.

Referring to FIG. 1B, an example network environment 100′ for deliveringand/or operating a computing network environment on a client 102 isshown. As shown in FIG. 1B, a server 106 may include an applicationdelivery system 190 for delivering a computing environment, application,and/or data files to one or more clients 102. Client 102 may includeclient agent 120 and computing environment 15. Computing environment 15may execute or operate an application, 16, that accesses, processes oruses a data file 17. Computing environment 15, application 16 and/ordata file 17 may be delivered to the client 102 via appliance 200 and/orthe server 106.

Appliance 200 may accelerate delivery of all or a portion of computingenvironment 15 to a client 102, for example by the application deliverysystem 190. For example, appliance 200 may accelerate delivery of astreaming application and data file processable by the application froma data center to a remote user location by accelerating transport layertraffic between a client 102 and a server 106. Such acceleration may beprovided by one or more techniques, such as: 1) transport layerconnection pooling, 2) transport layer connection multiplexing, 3)transport control protocol buffering, 4) compression, 5) caching, orother techniques. Appliance 200 may also provide load balancing ofservers 106 to process requests from clients 102, act as a proxy oraccess server to provide access to the one or more servers 106, providesecurity and/or act as a firewall between a client 102 and a server 106,provide Domain Name Service (DNS) resolution, provide one or morevirtual servers or virtual internet protocol servers, and/or provide asecure virtual private network (VPN) connection from a client 102 to aserver 106, such as a secure socket layer (SSL) VPN connection and/orprovide encryption and decryption operations.

Application delivery management system 190 may deliver computingenvironment 15 to a user (e.g., client 102), remote or otherwise, basedon authentication and authorization policies applied by policy engine195. A remote user may obtain a computing environment and access toserver stored applications and data files from any network-connecteddevice (e.g., client 102). For example, appliance 200 may request anapplication and data file from server 106. In response to the request,application delivery system 190 and/or server 106 may deliver theapplication and data file to client 102, for example via an applicationstream to operate in computing environment 15 on client 102, or via aremote-display protocol or otherwise via remote-based or server-basedcomputing. In an embodiment, application delivery system 190 may beimplemented as any portion of the Citrix Workspace Suite™ by CitrixSystems, Inc., such as XenApp® or XenDesktop®.

Policy engine 195 may control and manage the access to, and executionand delivery of, applications. For example, policy engine 195 maydetermine the one or more applications a user or client 102 may accessand/or how the application should be delivered to the user or client102, such as a server-based computing, streaming or delivering theapplication locally to the client 50 for local execution.

For example, in operation, a client 102 may request execution of anapplication (e.g., application 16′) and application delivery system 190of server 106 determines how to execute application 16′, for examplebased upon credentials received from client 102 and a user policyapplied by policy engine 195 associated with the credentials. Forexample, application delivery system 190 may enable client 102 toreceive application-output data generated by execution of theapplication on a server 106, may enable client 102 to execute theapplication locally after receiving the application from server 106, ormay stream the application via network 104 to client 102. For example,in some embodiments, the application may be a server-based or aremote-based application executed on server 106 on behalf of client 102.Server 106 may display output to client 102 using a thin-client orremote-display protocol, such as the Independent Computing Architecture(ICA) protocol by Citrix Systems, Inc. of Fort Lauderdale, Fla. Theapplication may be any application related to real-time datacommunications, such as applications for streaming graphics, streamingvideo and/or audio or other data, delivery of remote desktops orworkspaces or hosted services or applications, for exampleinfrastructure as a service (IaaS), workspace as a service (WaaS),software as a service (SaaS) or platform as a service (PaaS).

One or more of servers 106 may include a performance monitoring serviceor agent 197. In some embodiments, a dedicated one or more servers 106may be employed to perform performance monitoring. Performancemonitoring may be performed using data collection, aggregation,analysis, management and reporting, for example by software, hardware ora combination thereof. Performance monitoring may include one or moreagents for performing monitoring, measurement and data collectionactivities on clients 102 (e.g., client agent 120), servers 106 (e.g.,agent 197) or an appliance 200 and/or 205 (agent not shown). In general,monitoring agents (e.g., 120 and/or 197) execute transparently (e.g., inthe background) to any application and/or user of the device. In someembodiments, monitoring agent 197 includes any of the productembodiments referred to as EdgeSight by Citrix Systems, Inc. of FortLauderdale, Fla.

The monitoring agents 120 and 197 may monitor, measure, collect, and/oranalyze data on a predetermined frequency, based upon an occurrence ofgiven event(s), or in real time during operation of network environment100. The monitoring agents may monitor resource consumption and/orperformance of hardware, software, and/or communications resources ofclients 102, networks 104, appliances 200 and/or 205, and/or servers106. For example, network connections such as a transport layerconnection, network latency, bandwidth utilization, end-user responsetimes, application usage and performance, session connections to anapplication, cache usage, memory usage, processor usage, storage usage,database transactions, client and/or server utilization, active users,duration of user activity, application crashes, errors, or hangs, thetime required to log-in to an application, a server, or the applicationdelivery system, and/or other performance conditions and metrics may bemonitored.

The monitoring agents 120 and 197 may provide application performancemanagement for application delivery system 190. For example, based uponone or more monitored performance conditions or metrics, applicationdelivery system 190 may be dynamically adjusted, for exampleperiodically or in real-time, to optimize application delivery byservers 106 to clients 102 based upon network environment performanceand conditions.

In described embodiments, clients 102, servers 106, and appliances 200and 205 may be deployed as and/or executed on any type and form ofcomputing device, such as any desktop computer, laptop computer, ormobile device capable of communication over at least one network andperforming the operations described herein. For example, clients 102,servers 106 and/or appliances 200 and 205 may each correspond to onecomputer, a plurality of computers, or a network of distributedcomputers such as computer 101 shown in FIG. 1C.

As shown in FIG. 1C, computer 101 may include one or more processors103, volatile memory 122 (e.g., RAM), non-volatile memory 128 (e.g., oneor more hard disk drives (HDDs) or other magnetic or optical storagemedia, one or more solid state drives (SSDs) such as a flash drive orother solid state storage media, one or more hybrid magnetic and solidstate drives, and/or one or more virtual storage volumes, such as acloud storage, or a combination of such physical storage volumes andvirtual storage volumes or arrays thereof), user interface (UI) 123, oneor more communications interfaces 118, and communication bus 150. Userinterface 123 may include graphical user interface (GUI) 124 (e.g., atouchscreen, a display, etc.) and one or more input/output (I/O) devices126 (e.g., a mouse, a keyboard, etc.). Non-volatile memory 128 storesoperating system 115, one or more applications 116, and data 117 suchthat, for example, computer instructions of operating system 115 and/orapplications 116 are executed by processor(s) 103 out of volatile memory122. Data may be entered using an input device of GUI 124 or receivedfrom I/O device(s) 126. Various elements of computer 101 may communicatevia communication bus 150. Computer 101 as shown in FIG. 1C is shownmerely as an example, as clients 102, servers 106 and/or appliances 200and 205 may be implemented by any computing or processing environmentand with any type of machine or set of machines that may have suitablehardware and/or software capable of operating as described herein.

Processor(s) 103 may be implemented by one or more programmableprocessors executing one or more computer programs to perform thefunctions of the system. As used herein, the term “processor” describesan electronic circuit that performs a function, an operation, or asequence of operations. The function, operation, or sequence ofoperations may be hard coded into the electronic circuit or soft codedby way of instructions held in a memory device. A “processor” mayperform the function, operation, or sequence of operations using digitalvalues or using analog signals. In some embodiments, the “processor” canbe embodied in one or more application specific integrated circuits(ASICs), microprocessors, digital signal processors, microcontrollers,field programmable gate arrays (FPGAs), programmable logic arrays(PLAs), multi-core processors, or general-purpose computers withassociated memory. The “processor” may be analog, digital ormixed-signal. In some embodiments, the “processor” may be one or morephysical processors or one or more “virtual” (e.g., remotely located or“cloud”) processors.

Communications interfaces 118 may include one or more interfaces toenable computer 101 to access a computer network such as a LAN, a WAN,or the Internet through a variety of wired and/or wireless or cellularconnections.

In described embodiments, a first computing device 101 may execute anapplication on behalf of a user of a client computing device (e.g., aclient 102), may execute a virtual machine, which provides an executionsession within which applications execute on behalf of a user or aclient computing device (e.g., a client 102), such as a hosted desktopsession, may execute a terminal services session to provide a hosteddesktop environment, or may provide access to a computing environmentincluding one or more of: one or more applications, one or more desktopapplications, and one or more desktop sessions in which one or moreapplications may execute.

B. Appliance Architecture

FIG. 2 shows an example embodiment of appliance 200. As describedherein, appliance 200 may be implemented as a server, gateway, router,switch, bridge or other type of computing or network device. As shown inFIG. 2, an embodiment of appliance 200 may include a hardware layer 206and a software layer 205 divided into a user space 202 and a kernelspace 204. Hardware layer 206 provides the hardware elements upon whichprograms and services within kernel space 204 and user space 202 areexecuted and allow programs and services within kernel space 204 anduser space 202 to communicate data both internally and externally withrespect to appliance 200. As shown in FIG. 2, hardware layer 206 mayinclude one or more processing units 262 for executing software programsand services, memory 264 for storing software and data, network ports266 for transmitting and receiving data over a network, and encryptionprocessor 260 for encrypting and decrypting data such as in relation toSecure Socket Layer (SSL) or Transport Layer Security (TLS) processingof data transmitted and received over the network.

An operating system of appliance 200 allocates, manages, or otherwisesegregates the available system memory into kernel space 204 and userspace 202. Kernel space 204 is reserved for running kernel 230,including any device drivers, kernel extensions or other kernel relatedsoftware. As known to those skilled in the art, kernel 230 is the coreof the operating system, and provides access, control, and management ofresources and hardware-related elements of application. Kernel space 204may also include a number of network services or processes working inconjunction with cache manager 232.

Appliance 200 may include one or more network stacks 267, such as aTCP/IP based stack, for communicating with client(s) 102, server(s) 106,network(s) 104, and/or other appliances 200 or 205. For example,appliance 200 may establish and/or terminate one or more transport layerconnections between clients 102 and servers 106. Each network stack 267may include a buffer for queuing one or more network packets fortransmission by appliance 200.

Kernel space 204 may include cache manager 232, packet engine 240,encryption engine 234, policy engine 236 and compression engine 238. Inother words, one or more of processes 232, 240, 234, 236 and 238 run inthe core address space of the operating system of appliance 200, whichmay reduce the number of data transactions to and from the memory and/orcontext switches between kernel mode and user mode, for example sincedata obtained in kernel mode may not need to be passed or copied to auser process, thread or user level data structure.

Cache manager 232 may duplicate original data stored elsewhere or datapreviously computed, generated or transmitted to reduce the access timeof the data. In some embodiments, the cache manager 232 may be a dataobject in memory 264 of appliance 200, or may be a physical memoryhaving a faster access time than memory 264.

Policy engine 236 may include a statistical engine or otherconfiguration mechanism to allow a user to identify, specify, define orconfigure a caching policy and access, control and management ofobjects, data or content being cached by appliance 200, and define orconfigure security, network traffic, network access, compression orother functions performed by appliance 200.

Encryption engine 234 may process any security related protocol, such asSSL or TLS. For example, encryption engine 234 may encrypt and decryptnetwork packets, or any portion thereof, communicated via appliance 200,may setup or establish SSL, TLS or other secure connections, for examplebetween client 102, server 106, and/or other appliances 200 or 205. Insome embodiments, encryption engine 234 may use a tunneling protocol toprovide a VPN between a client 102 and a server 106. In someembodiments, encryption engine 234 is in communication with encryptionprocessor 260. Compression engine 238 compresses network packetsbi-directionally between clients 102 and servers 106 and/or between oneor more appliances 200.

Packet engine 240 may manage kernel-level processing of packets receivedand transmitted by appliance 200 via network stacks 267 to send andreceive network packets via network ports 266. Packet engine 240 mayoperate in conjunction with encryption engine 234, cache manager 232,policy engine 236 and compression engine 238, for example to performencryption/decryption, traffic management such as request-level contentswitching and request-level cache redirection, and compression anddecompression of data.

User space 202 is a memory area or portion of the operating system usedby user mode applications or programs otherwise running in user mode. Auser mode application may not access kernel space 204 directly and usesservice calls in order to access kernel services. User space 202 mayinclude graphical user interface (GUI) 210, a command line interface(CLI) 212, shell services 214, health monitor 216, and daemon services218. GUI 210 and CLI 212 enable a system administrator or other user tointeract with and control the operation of appliance 200, such as viathe operating system of appliance 200. Shell services 214 includeprograms, services, tasks, processes or executable instructions tosupport interaction with appliance 200 by a user via the GUI 210 and/orCLI 212.

Health monitor 216 monitors, checks, reports and ensures that networksystems are functioning properly and that users are receiving requestedcontent over a network, for example by monitoring activity of appliance200. In some embodiments, health monitor 216 intercepts and inspects anynetwork traffic passed via appliance 200. For example, health monitor216 may interface with one or more of encryption engine 234, cachemanager 232, policy engine 236, compression engine 238, packet engine240, daemon services 218, and shell services 214 to determine a state,status, operating condition, or health of any portion of the appliance200. Further, health monitor 216 may determine whether a program,process, service or task is active and currently running, check status,error or history logs provided by any program, process, service or taskto determine any condition, status or error with any portion ofappliance 200. Additionally, health monitor 216 may measure and monitorthe performance of any application, program, process, service, task orthread executing on appliance 200.

Daemon services 218 are programs that run continuously or in thebackground and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests toother programs or processes, such as another daemon service 218 asappropriate.

As described herein, appliance 200 may relieve servers 106 of much ofthe processing load caused by repeatedly opening and closing transportlayer connections to clients 102 by opening one or more transport layerconnections with each server 106 and maintaining these connections toallow repeated data accesses by clients via the Internet (e.g.,“connection pooling”). To perform connection pooling, appliance 200 maytranslate or multiplex communications by modifying sequence numbers andacknowledgment numbers at the transport layer protocol level (e.g.,“connection multiplexing”). Appliance 200 may also provide switching orload balancing for communications between the client 102 and server 106.

As described herein, each client 102 may include client agent 120 forestablishing and exchanging communications with appliance 200 and/orserver 106 via a network 104. Client 102 may have installed and/orexecute one or more applications that are in communication with network104. Client agent 120 may intercept network communications from anetwork stack used by the one or more applications. For example, clientagent 120 may intercept a network communication at any point in anetwork stack and redirect the network communication to a destinationdesired, managed or controlled by client agent 120, for example tointercept and redirect a transport layer connection to an IP address andport controlled or managed by client agent 120. Thus, client agent 120may transparently intercept any protocol layer below the transportlayer, such as the network layer, and any protocol layer above thetransport layer, such as the session, presentation or applicationlayers. Client agent 120 can interface with the transport layer tosecure, optimize, accelerate, route or load-balance any communicationsprovided via any protocol carried by the transport layer.

In some embodiments, client agent 120 is implemented as an IndependentComputing Architecture (ICA) client developed by Citrix Systems, Inc. ofFort Lauderdale, Fla. Client agent 120 may perform acceleration,streaming, monitoring, and/or other operations. For example, clientagent 120 may accelerate streaming an application from a server 106 to aclient 102. Client agent 120 may also perform end-pointdetection/scanning and collect end-point information about client 102for appliance 200 and/or server 106. Appliance 200 and/or server 106 mayuse the collected information to determine and provide access,authentication and authorization control of the client's connection tonetwork 104. For example, client agent 120 may identify and determineone or more client-side attributes, such as: the operating system and/ora version of an operating system, a service pack of the operatingsystem, a running service, a running process, a file, presence orversions of various applications of the client, such as antivirus,firewall, security, and/or other software.

C. Systems and Methods for Providing Virtualized Application DeliveryController

Referring now to FIG. 3, a block diagram of a virtualized environment300 is shown. As shown, a computing device 302 in virtualizedenvironment 300 includes a virtualization layer 303, a hypervisor layer304, and a hardware layer 307. Hypervisor layer 304 includes one or morehypervisors (or virtualization managers) 301 that allocates and managesaccess to a number of physical resources in hardware layer 307 (e.g.,physical processor(s) 321 and physical disk(s) 328) by at least onevirtual machine (VM) (e.g., one of VMs 306) executing in virtualizationlayer 303. Each VM 306 may include allocated virtual resources such asvirtual processors 332 and/or virtual disks 342, as well as virtualresources such as virtual memory and virtual network interfaces. In someembodiments, at least one of VMs 306 may include a control operatingsystem (e.g., 305) in communication with hypervisor 301 and used toexecute applications for managing and configuring other VMs (e.g., guestoperating systems 310) on device 302.

In general, hypervisor(s) 301 may provide virtual resources to anoperating system of VMs 306 in any manner that simulates the operatingsystem having access to a physical device. Thus, hypervisor(s) 301 maybe used to emulate virtual hardware, partition physical hardware,virtualize physical hardware, and execute virtual machines that provideaccess to computing environments. In an illustrative embodiment,hypervisor(s) 301 may be implemented as a XEN hypervisor, for example asprovided by the open source Xen.org community. In an illustrativeembodiment, device 302 executing a hypervisor that creates a virtualmachine platform on which guest operating systems may execute isreferred to as a host server. In such an embodiment, device 302 may beimplemented as a XEN server as provided by Citrix Systems, Inc., of FortLauderdale, Fla.

Hypervisor 301 may create one or more VMs 306 in which an operatingsystem (e.g., control operating system 305 and/or guest operating system310) executes. For example, the hypervisor 301 loads a virtual machineimage to create VMs 306 to execute an operating system. Hypervisor 301may present VMs 306 with an abstraction of hardware layer 307, and/ormay control how physical capabilities of hardware layer 307 arepresented to VMs 306. For example, hypervisor(s) 301 may manage a poolof resources distributed across multiple physical computing devices.

In some embodiments, one of VMs 306 (e.g., the VM executing controloperating system 305) may manage and configure other of VMs 306, forexample by managing the execution and/or termination of a VM and/ormanaging allocation of virtual resources to a VM. In variousembodiments, VMs may communicate with hypervisor(s) 301 and/or other VMsvia, for example, one or more Application Programming Interfaces (APIs),shared memory, and/or other techniques.

In general, VMs 306 may provide a user of device 302 with access toresources within virtualized computing environment 300, for example, oneor more programs, applications, documents, files, desktop and/orcomputing environments, or other resources. In some embodiments, VMs 306may be implemented as fully virtualized VMs that are not aware that theyare virtual machines (e.g., a Hardware Virtual Machine or HVM). In otherembodiments, the VM may be aware that it is a virtual machine, and/orthe VM may be implemented as a paravirtualized (PV) VM.

Although shown in FIG. 3 as including a single virtualized device 302,virtualized environment 300 may include a plurality of networked devicesin a system in which at least one physical host executes a virtualmachine. A device on which a VM executes may be referred to as aphysical host and/or a host machine. For example, appliance 200 may beadditionally or alternatively implemented in a virtualized environment300 on any computing device, such as a client 102, server 106 orappliance 200. Virtual appliances may provide functionality foravailability, performance, health monitoring, caching and compression,connection multiplexing and pooling and/or security processing (e.g.,firewall, VPN, encryption/decryption, etc.), similarly as described inregard to appliance 200.

In some embodiments, a server may execute multiple virtual machines 306,for example on various cores of a multi-core processing system and/orvarious processors of a multiple processor device. For example, althoughgenerally shown herein as “processors” (e.g., in FIGS. 1C, 2 and 3), oneor more of the processors may be implemented as either single- ormulti-core processors to provide a multi-threaded, parallel architectureand/or multi-core architecture. Each processor and/or core may have oruse memory that is allocated or assigned for private or local use thatis only accessible by that processor/core, and/or may have or use memorythat is public or shared and accessible by multiple processors/cores.Such architectures may allow work, task, load or network trafficdistribution across one or more processors and/or one or more cores(e.g., by functional parallelism, data parallelism, flow-based dataparallelism, etc.).

Further, instead of (or in addition to) the functionality of the coresbeing implemented in the form of a physical processor/core, suchfunctionality may be implemented in a virtualized environment (e.g.,300) on a client 102, server 106 or appliance 200, such that thefunctionality may be implemented across multiple devices, such as acluster of computing devices, a server farm or network of computingdevices, etc. The various processors/cores may interface or communicatewith each other using a variety of interface techniques, such as core tocore messaging, shared memory, kernel APIs, etc.

In embodiments employing multiple processors and/or multiple processorcores, described embodiments may distribute data packets among cores orprocessors, for example to balance the flows across the cores. Forexample, packet distribution may be based upon determinations offunctions performed by each core, source and destination addresses,and/or whether: a load on the associated core is above a predeterminedthreshold; the load on the associated core is below a predeterminedthreshold; the load on the associated core is less than the load on theother cores; or any other metric that can be used to determine where toforward data packets based in part on the amount of load on a processor.

For example, data packets may be distributed among cores or processesusing receive-side scaling (RSS) in order to process packets usingmultiple processors/cores in a network. RSS generally allows packetprocessing to be balanced across multiple processors/cores whilemaintaining in-order delivery of the packets. In some embodiments, RSSmay use a hashing scheme to determine a core or processor for processinga packet.

The RSS may generate hash values from any type and form of input, suchas a sequence of values. This sequence of values can include any portionof the network packet, such as any header, field or payload of networkpacket, and include any tuples of information associated with a networkpacket or data flow, such as addresses and ports. The hash result or anyportion thereof may be used to identify a processor, core, engine, etc.,for distributing a network packet, for example via a hash table,indirection table, or other mapping technique.

D. Systems and Methods for Providing a Distributed Cluster Architecture

Although shown in FIGS. 1A and 1B as being single appliances, appliances200 may be implemented as one or more distributed or clusteredappliances. Individual computing devices or appliances may be referredto as nodes of the cluster. A centralized management system may performload balancing, distribution, configuration, or other tasks to allow thenodes to operate in conjunction as a single computing system. Such acluster may be viewed as a single virtual appliance or computing device.FIG. 4 shows a block diagram of an illustrative computing device clusteror appliance cluster 400. A plurality of appliances 200 or othercomputing devices (e.g., nodes) may be joined into a single cluster 400.Cluster 400 may operate as an application server, network storageserver, backup service, or any other type of computing device to performmany of the functions of appliances 200 and/or 205.

In some embodiments, each appliance 200 of cluster 400 may beimplemented as a multi-processor and/or multi-core appliance, asdescribed herein. Such embodiments may employ a two-tier distributionsystem, with one appliance if the cluster distributing packets to nodesof the cluster, and each node distributing packets for processing toprocessors/cores of the node. In many embodiments, one or more ofappliances 200 of cluster 400 may be physically grouped orgeographically proximate to one another, such as a group of bladeservers or rack mount devices in a given chassis, rack, and/or datacenter. In some embodiments, one or more of appliances 200 of cluster400 may be geographically distributed, with appliances 200 notphysically or geographically co-located. In such embodiments,geographically remote appliances may be joined by a dedicated networkconnection and/or VPN. In geographically distributed embodiments, loadbalancing may also account for communications latency betweengeographically remote appliances.

In some embodiments, cluster 400 may be considered a virtual appliance,grouped via common configuration, management, and purpose, rather thanas a physical group. For example, an appliance cluster may comprise aplurality of virtual machines or processes executed by one or moreservers.

As shown in FIG. 4, appliance cluster 400 may be coupled to aclient-side network 104 via client data plane 402, for example totransfer data between clients 102 and appliance cluster 400. Client dataplane 402 may be implemented a switch, hub, router, or other similarnetwork device internal or external to cluster 400 to distribute trafficacross the nodes of cluster 400. For example, traffic distribution maybe performed based on equal-cost multi-path (ECMP) routing with nexthops configured with appliances or nodes of the cluster, open-shortestpath first (OSPF), stateless hash-based traffic distribution, linkaggregation (LAG) protocols, or any other type and form of flowdistribution, load balancing, and routing.

Appliance cluster 400 may be coupled to a second network 104′ via serverdata plane 404. Similar to client data plane 402, server data plane 404may be implemented as a switch, hub, router, or other network devicethat may be internal or external to cluster 400. In some embodiments,client data plane 402 and server data plane 404 may be merged orcombined into a single device.

In some embodiments, each appliance 200 of cluster 400 may be connectedvia an internal communication network or backplane 406. Backplane 406may enable inter-node or inter-appliance control and configurationmessages, for inter-node forwarding of traffic, and/or for communicatingconfiguration and control traffic from an administrator or user tocluster 400. In some embodiments, backplane 406 may be a physicalnetwork, a VPN or tunnel, or a combination thereof.

E. Systems and Methods for Providing and Using a Virtual Channel toProvide Insights

Described herein are systems and methods for providing insights ormetrics in connection with provisioning applications and/or desktopsessions to end-users. Network devices (e.g., appliances, intermediarydevices, gateways, proxy devices or middle-boxes) such as Citrix Gatewayand Citrix software-defined wide area network (SD-WAN) devices cangather insights such as network-level statistics. Additional insights(e.g., metadata and metrics) associated with virtual applications andvirtual desktops can be gathered to provide administrators withcomprehensive end-to-end real-time and/or historical reports ofperformance and end-user experience (UX) insights. In some embodiments,to obtain the insights, the network devices may have to perform deepparsing of virtualization and other protocols such as Citrix independentcomputing architecture (ICA), remote desktop protocol (RDP), or Citrixhigh definition experience (HDX), along with some or all associatedvirtual channels (VCs).

This deep parsing can demand or entail knowledge of all underlyingprotocol details, and can be resource intensive. The effort for anetwork device to deeply parse, decrypt and/or decompress traffic (e.g.,HDX traffic) can hurt the scalability of the network device and cansignificantly increase the cost of supporting (e.g., HDX specific)insights. These can be memory and CPU intensive operations that directlyaffect the number of connections (e.g., ICA connections) that a networkdevice (e.g., Citrix Gateway or SD-WAN appliance) can support at a time.Deep parsing of such traffic can be a memory and CPU intensiveoperation, mainly because of the stateful decompression of the ICAstream. “Stateful” can refer to maintaining, tracking, keeping, storingand/or transitioning of state(s) across connections, sessions, timeand/or operations, for example.

To address these and other challenges, the present disclosure providesembodiments of methods and systems for delivering insights of a virtualsession to a network device in a real-time, scalable and/or extensiblemanner (e.g., without deep parsing by a network device). In someembodiments, a separate or independent VC (sometimes referred to as anApp Flow VC) can be established across or between a client-side agent(e.g., desktop virtualization client), network device(s) and aserver-side agent (e.g., VDA) for the transmission of insights (e.g.,virtualization session insights). The App Flow VC can be negotiatedbetween these entities (e.g., between the desktop virtualization client,network appliances and VDA). The App Flow VC can facilitate scalable andextensible processing of insights. The App Flow VC can remainnon-interleaved with other VCs in a HDX/ICA stream, and the stream canbe uncompressed to facilitate access to and parsing of the App Flow VC.Such simple parsing consumes significantly lower levels of resources,and improves the operation of the network device by allowing moreresources of the network device to perform any other functions, such asto process a larger number of connections (e.g., ICA connections) at agiven time. Even if a larger number of connections is not necessary,lower consumption of CPU resources for instance results in lower powerconsumption (e.g., lower energy wastage to obtain similar insights)and/or heat generation, as compared with deep parsing. Hence, thepresent system and methods allow for substantive improvements in theoperation of system components such as network devices (e.g., SD-WAN andgateway devices).

Further, embodiments of the present methods and system can improve theHDX/ICA platform in addition ways. For example, embodiments of thepresent methods and system can provide or support state transition ofApp Flow insights or metrics during network device failover (e.g.,high-availability failover), hence improving operation during suchfailover. Certain embodiments of the present methods and system provideor support efficient identification and prioritization of Multi-streamICA (MSI) HDX streams, which reduces resources to access and processdata from such streams. Some embodiments of the present methods andsystem provide or support layer 7 (L7, application layer) latencycalculation and communication independent of server processing time.Some embodiments of the present methods and system provide or support L7latency calculation and communication between multiple network devices.Hence, these solutions can provide metrics that more accuratelycharacterizes the health and performance of specific network components,segments or connections.

In an ICA or HDX configuration for instance, VCs can support a remotecomputing experience at a client 102, by providing access to one or moreapplications and/or remote desktops hosted on a server 106. As shown inFIG. 5, VCs can be established using a server-side agent 504 and aclient-side agent 502. As illustrated in FIG. 5, the system 500 caninclude a client 102 with a client-side agent 502 (e.g., Workspace App),a server 106 with a server-side agent 504 (e.g., VDA), ICA stacks oneach of the client 102 and the server 106, that supports the HDX sessionvia a network link. Each of the ICA stacks 516 a-n can include aWinStation driver (WD) 516 a, a protocol driver (PD) 516 b, and/or atransport driver (TD) 516 c, each involving one or more correspondingprotocols.

VCs can support communications and functionalities between the client102 and the server 106, in provisioning an application or desktop viaremote delivery to the client 102. Virtual channels can provide a secureway for an application running on the server 106 to communicate with theclient 102 or the client-side environment. Each virtual channel cansupport communications for supporting or enabling one or morefunctionalities of the application or desktop, such as graphics, disks,COM ports, LPT ports, printers, audio, video, smart card, and so on, sothat these functionalities are available across the client 102 and theserver 106. Some virtual channels can be loaded or established in usermode 510, and some others can be loaded or established in kernel mode512. Virtual channels established in the user mode 510 may have limitedaccess to the functionalities of the client 102 or the server 106 (e.g.,those allocated to the application for the virtual channel). Conversely,virtual channels established in the kernel mode 512 may have full ormore expansive access to the functionalities of the client 102 or theserver 106 (e.g., besides those allocated to the application). A clientvirtual channel, for example, can be routed through a WinStation driver520 a (e.g., in the server-side ICA stack 520 a-n), and can be polled oraccessed on the client-side by a corresponding WinStation driver 516 a(e.g., in the client-side ICA stack 516 a-n). On the client side,virtual channels can correspond to virtual drivers each providing aspecific function. The virtual drivers can operate at the presentationlayer protocol level for instance (or another protocol level). There canbe a number of these protocols active at any given time by multiplexingchannels that are provided by for instance the WinStation protocol layer(or WinStation driver). Multiple virtual channels can be combined ormultiplexed within a provisioning session (e.g., an ICA/HDX session ortraffic stream).

Virtual channels can be created by virtualizing one or more “physical”channels, each virtualized into one or more virtual channels. Forexample, several virtual channels may be identified separately and cancarry different types of communications, but may share the same portcorresponding to a physical channel. The use of virtual channels canallow sharing or data multiplexing on a single non-virtual channel tosupport multiple streams of information. One or more virtual channelsmay operate to communicate presentation layer elements from the server106 to the client device 102. Some of these virtual channels maycommunicate commands, function calls or other messages from the clientdevice 102 to an application or a remote desktop's operating system.These messages may be used to control, update or manage the operationand display of the application or desktop.

By way of example, a client-side agent 502 may receive, from aserver-side agent 504 via a provisioning (e.g., ICA, RDP, HDX) session,data associated with a remote desktop environment generated on a server106 (e.g., a Citrix Virtual Desktops server). In some embodiments, theclient-side agent 502 may be provided as a dynamically linked librarycomponent for example, that receives window creation and window processdata from the server-side agent 504 for use in displaying a localversion of a window generated on the server 106. In some embodiments,the client-side agent 502 may receive data such as window attribute dataover one or more connections. The one or more connections may bemultiplexed into one or more virtual channels. Such multiplexing mayallow for different virtual channels to have different bandwidth limitsor different priorities, while still being part of a single transportlayer connection. This can reduce the transport layer overhead requiredand provide for SSL or VPN tunnel capability, while still allowingper-channel compression, buffering, and/or management of communicationpriority between the client-side agent 502 and the server-side agent504. The virtual channels may be dedicated to specific content types orpurposes. For example, a first high-priority virtual channel may bededicated to transmission of application output data, while a secondlow-priority virtual channel may be dedicated to transmission of taskbarthumbnail images. A plurality of virtual channels can be used forcommunicating one or more types of application data (e.g., audio,graphics, metadata, printer data, disk data, smart card data, and soon). For instance, some types of application data can each be conveyedor communication via a dedicated virtual channel within the provisioningsession, and/or certain types of application data can each be conveyedor communication to the intermediary device by sharing one or morevirtual channels.

In a HDX session for delivering an application or desktop (e.g., viaCitrix Virtual Apps and Desktops), the protocol exchange between aclient-side agent (e.g., Citrix Workspace App) and a server-side agent(e.g., Citrix Virtual Apps and Desktops virtual delivery agent (VDA))can involve multiple protocols including a core ICA protocol, andprotocols for VCs representing various technologies, such as graphics,multimedia, printing, drive mapping, windowing, user input, etc. Deepparsing (e.g., decompression, decoding, decryption and/orde-interleaving) of such virtualization protocols and/or VC data streamscan consume significant processing resources and greatly limit thescalability of network devices. For instance, network devices (e.g.,Citrix Gateway and SD-WAN) can deeply parse ICA traffic flowing througha network, having one or more protocols such as transmission controlprotocol (TCP) or transport layer security (TLS), enlightened datatransport (EDT) or datagram transport layer security (DTLS) or userdatagram protocol (UDP), common gateway protocol (CGP), ICA framing,custom ICA encryption (e.g. secure ICA), ICA protocol itself (e.g.,including compression, such as stateful context-based compression) andde-interleaving of individual core ICA or VC data streams, and theindividual VC protocols in order to gather various information orinsights from a HDX session for instance.

In addition to HDX, RDP or ICA based sessions, other types ofcommunications sessions are contemplated that can include variouschannels or connections of data streams (e.g., with features similar tovirtual channels), and may involve various corresponding protocols.Insights, metrics, analytics, statistics and/or other information(hereafter sometimes generally referred to as insights) relating to thecommunication session can be used to determine and/or improve userexperience and the overall health of the infrastructure of thecommunications session (e.g., Citrix Virtual Apps and Desktopsinfrastructure), and the applications (e.g., Microsoft Officeapplications, remote desktop application) being delivered using theinfrastructure. The insights can be combined with other network-healthanalysis performed by network devices, and/or processed and/or used bythe network devices (e.g. Citrix Gateway or Citrix SD-WAN), to forinstance adapt or improve certain operation(s). In addition, suchcollective insights may be provided to a management and triaging utility(e.g. Citrix Director), a management analytics service, or a third-partycollector tool. The collective insights and/or these tools can allowadministrators to view and analyze real-time client, host and networklatency metrics, historical reports and/or end-to-end performance data,and can allow the administrators to troubleshoot performance and networkissues.

However, the effort for a network device to deeply parse, decrypt and/ordecompress traffic (e.g., HDX traffic) can hurt or limit the scalabilityof the network device and can significantly increase the cost ofsupporting (e.g., HDX specific) insights. These can be memory and CPUintensive operations that directly affect the number of connections(e.g., ICA connections) that a network device (e.g., Citrix Gateway orSD-WAN appliance) can support at a time. Deep parsing of such trafficcan be a memory and CPU intensive operation, mainly because of thestateful decompression of the ICA stream. “Stateful” can refer tomaintaining, tracking, keeping, storing and/or transitioning of state(s)across connections, sessions, time and/or operations, for example.

In some embodiments, adding additional insights for retrieval by anetwork device may entail updating one or more of the session protocols(e.g., the HDX protocols). Parsing multi-stream ICA (MSI) streams canfurther complicate the network device's parsing mechanism, logic and/ormethods. High-availability (HA) failovers from one network device toanother can also be complicated by the process or requirement oftransitioning very large and complex state between the devices in orderto continue gathering insights. High-availability, for instance, canrefer to a system being tolerant to failure, such as using hardwareredundancy. In some embodiments, measuring the roundtrip latency betweenclient-side and server-side agents (e.g., Citrix Workspace App and VDA)can be affected by server load and server processing time.

To address these and other challenges, the present disclosure providesembodiments of methods and systems for delivering insights of a virtualsession to a network device in a real-time, scalable and/or extensiblemanner (e.g., without deep parsing by a network device). In someembodiments, a separate or independent VC (sometimes referred to as anApp Flow VC) can be established across or between a client-side agent(e.g., desktop virtualization client), network device(s) and aserver-side agent (e.g., VDA) for the transmission of insights (e.g.,virtualization session insights). The App Flow VC can be negotiatedbetween these entities (e.g., between the desktop virtualization client,network appliances and VDA). The App Flow VC can facilitate scalable andextensible processing of insights.

Some embodiments of the present methods and systems provide or supportstate transition of App Flow insights or metrics during network devicefailover (e.g., high-availability failover). Certain embodiments of thepresent methods and systems provide or support efficient identificationand prioritization of MSI HDX streams. Some embodiments of the presentmethods and systems provide or support layer 7 (e.g., L7, applicationlayer) latency calculation and communication independent of hostprocessing time. Some embodiments of the present methods and systemsprovide or support L7 latency calculation and communication betweenmultiple network devices.

Referring again to FIG. 5, the system 500 can incorporate an App Flow VC(e.g., virtual channel 514 or 522) for providing insights, according toan illustrative embodiment. The App Flow VC can incorporate one or morefeatures of the VCs discussed above. In some aspects, the App Flow VCcan be identical or similar to other VCs except that the App Flow VC isconfigured to carry a different type of data stream than that carried bythe other VCs. The network link 518, which can include the client 102,server 106 and the ICA stacks, can communicate a data stream of the AppFlow VC. The data stream can carry insights (e.g., in packets, frames orother messages) that can be accessed by device(s) in the network link518.

The systems and methods of the present disclosure may be implementedusing or involving any type and form of device, including clients,servers and/or appliances 200 described above with reference to FIG.1A-FIG. 1B, FIG. 2 and FIG. 4. As referenced herein, a “server” maysometimes refer to any device in a client-server relationship, e.g., anappliance 200 in a handshake with a client device 102. The server 106may be an instance, implementation, or include aspects similar to server106 a-n described above with reference to at least FIG. 1A. Similarly,the client 102 may be an instance, implementation, or include aspectssimilar to any of the clients 102 a-n described above with reference toFIG. 1A. The present systems and methods may be implemented using orinvolving an intermediary device or gateway, such as any embodiments oraspects of the appliance or devices 200 described herein. The systemsand methods may be implemented in any type and form of environment,including multi-core devices, virtualized environments and/or clusteredenvironments as described herein.

The server 106 may host one or more applications or services. Each ofthe applications or services can include or correspond to any type orform of application or service. The application or service may include anetwork application, a web application, a Software-as-a-Service (SaaS)application, a remote-hosted application, and so on. As somenon-limiting examples, an application can include a word processing,spreadsheet or other application from a suite of applications (e.g.,Microsoft Office360, or Google docs), an application hosted andexecuting on a server for remote provisioning to a client, a desktopapplication, and/or a HTML5-based application. Packets corresponding toan application or service 510 may be compressed, encrypted and/orotherwise processed by the VDA and/or ICA stack (sometimes referred toas HDX stack, or VDA HDX stack) of the server 106, and transmitted ordelivered to the client 102. The VDA may include the ICA stack 520 a-n(e.g., WD 520 a, PD 520 b, and TD 520 c), and can terminate one end of aVC at the server-side agent 504, with the client-side agent 502terminating the other end of the VC.

In some embodiments, the client 102 may reside at a branch office or anorganization for instance, and may operate within a client-side network,which may include or correspond to a private network (e.g., a local areanetwork (LAN) or wide area network (WAN)). In some embodiments, theserver 106 and the client 102 may be communicably coupled to one anothervia a private network (e.g., a LAN or a software-defined wide areanetwork (SD-WAN)). The server 106 may reside at a server or data center,and may operate within a server-side network, which may also be aprivate network (e.g., a LAN, WAN, etc.).

One or more network devices can be intermediary between the client 102and the server 106. A network device 508 can include or correspond toany type or form of intermediary device, network device or appliance,gateway device, middle box device and/or proxy device, such as but notlimited to a NetScaler device, SD-WAN device, and so on. Each of theserver 106, client 102, and network device(s) in the network link 518may be communicably coupled in series.

Negotiation and Establishment of an App Flow VC for Transmission ofInsights

The server-side agent 504 (e.g., VDA) executing on the server 106 mayinitiate establishment of an App Flow VC. The server-side agent 504 mayinitiate establishment of an App Flow VC with a client-side agent 502(e.g., a desktop virtualization client) and/or network device(s) in thepath between the server 106 and the client 102. All or some of theserver-side agent 504, the client-side agent 502 (e.g., Citrix WorkspaceApp (CWA) or Citrix Receiver), and the network device(s) (e.g., CitrixGateway, Citrix Gateway Service, Citrix SD-WAN) along the network linkcan choose to participate in the negotiation of the App Flow VC. Thesedevice(s) can advertise their presence and/or capabilities to supportthe App Flow VC.

For example, the server-side agent's HDX stack can initiate, establishor otherwise enable the App Flow VC, and can send its host-to-client(e.g., server 106 to client 102) insights data on a HDX connection(e.g., using ICA or Common Gateway Protocol (CGP)). The HDX connectionmay be the same as a HDX connection for carrying one or more other VCs(or HDX VCs), except that the App Flow VC that it carries may beuncompressed and/or non-interleaved with any other HDX VC(s). This is tofacilitate efficient parsing of the App Flow VC by network device(s) inthe network connection. Any of network device(s) and the client-sideagent 502 (e.g., Receiver) may parse and interpret, or simply ignore theinsights data in the App Flow VC. Within the App Flow VC, insights datamay be sent in a self-descriptive, light-weight extensible format, e.g.in JavaScript Object Notation (JSON) format.

Similarly, the client-side agent's HDX stack may establish or enable theApp Flow VC, and send its client-to-host (e.g., client 102 to server106) insights data via the App Flow VC. The App Flow VC may remainuncompressed and/or non-interleaved with other HDX VCs to facilitateefficient parsing by network device(s). The server-side agent 504 (e.g.,VDA) may parse and interpret, or simply ignore the client-to-hostinsights data in the App Flow VC.

In some embodiments, an App Flow protocol capability or data structureis used to negotiate a configuration (e.g., capabilities) for the AppFlow VC, which can include advertising support for the App Flow VC bydifferent entities (e.g., along the network link) to certain entities(e.g., client 102, server 106). The entities can advertise their supportfor the App Flow VC by performing capabilities exchange between theentities. The entities that are involved in the negotiation can includeat least one of the following: (a) server 106 (host), (b) network deviceA (e.g., gateway), (c) server-side network device B (e.g., SD-WANdevice), (d) client-side network device C (e.g., SD-WAN device), orclient 102. The capabilities exchange between the entities can determinea behavior of App Flow VC for a particular HDX session. More than onenetwork device (e.g., gateway device, SD-WAN device) may participate inthe negotiation. The capabilities exchange can include an entityreporting or advertising an App Flow capability of the entity to one ormore entities, or exchanging its App Flow capability with that of one ormore other entities.

In some embodiments, the App Flow VC capability may include at least oneof the following information or data fields:

Host (or server) Protocol Version

Host (or server) Flags

Gateway Protocol Version

Gateway Flags

Host (or server) side SD-WAN Protocol Version

Host (or server) side SD-WAN Flags

Client-side SD-WAN Protocol Version

Client-side SD-WAN Flags

Client Protocol Version

Client Flags

Session Protocol Version

Session Protocol Flags

Referring to FIG. 6, a method 600 of negotiating for and using an AppFlow VC is depicted, in accordance with an illustrative example. Alsodepicted in FIG. 6 is a client-side agent 502, a server-side agent 504,network device(s) 604, and a management tool or service 602, thatinteroperate in connection with the method. As illustrated, variousembodiments of the method can include all or some of a number ofoperations 1 through 8′.

Referring to operation 1, the server-side agent 504 (e.g., VDA) mayreport a new App Flow capability in a message (e.g., init-requestmessage or packet). If the server 106 does not support the App Flow VCfeature or if the App Flow VC feature is disabled in the server 106, theApp Flow capability of the server-side agent 504 is not sent to theother entities. Otherwise, the server 106 sends the App Flow capabilitywith the server's protocol version set to the highest version that theserver can support. The server may also set additional flags (e.g.,including one or more flags listed above) identifying granular App Flowfeatures. In some embodiments, all or some other data fields (e.g.,described above) are initially set to zero (e.g., set to 0 by default,or blanked out). The App flow capability may be sent in the message(e.g., an ICA init-request packet) from the server 106 to the client102.

Referring to operation 2, a network device 604 can set its networkdevice (e.g., gateway or SD-WAN) protocol version in the App Flowcapability in the message (e.g., init-request message or packet). Eachnetwork device 604 in the server-to-client path (e.g., in the networklink) may receive or intercept the message (e.g., init-request packet).The corresponding network device may parse the App Flow capability inturn along the server-to-client path, and set the corresponding networkdevice's respective App Flow protocol version to the highest version itcan support. Each network device 604 may also set additional flags(e.g., including one or more flags listed above) identifying granularApp Flow features. A protocol version of 0 (e.g., the initial/defaultvalue of 0 remains unchanged or is not set by a corresponding networkdevice) may indicate that the corresponding network device is notpresent in between the server 106 and the client 102 in the networklink. If the corresponding network device residing between the server106 and the client 102 does not support the App Flow protocol or if theApp Flow feature is disabled at the corresponding network device, thecapability is left unchanged (e.g., the protocol version remains zero).All other data fields in the App Flow capability are left unmodified.

Referring to operation 3, the client-side agent 502 (e.g., WorkspaceApp) may report the capability for the WinStation Driver at theclient-side ICA/HDX stack, in the message (e.g., init-response messageor packet). If the client 102 does not support the App Flow feature orthe feature is disabled at the client 102, the capability is not sentback to the host (e.g., the init-response packet is not transmitted backto the server 106). The capability is also not sent back to the server106 if there is no network device present between the client 102 and theserver 106, and/or there is no server-side agent 504 support for the AppFlow VC feature, as indicated by the respective protocol version datafields being zero (e.g., protocol versions of all possible networkdevices are blanked out or set to zero, and/or protocol version ofserver 106 is blanked out or set to zero), or lack of App Flowcapability being reported by the server 106. Otherwise, the client 102can send back the App Flow capability to the host, mirroring ormaintaining all server and network device data fields that have alreadybeen set. The client 102 can set the client's protocol version to thehighest version it can support. The client 102 may also set additionalflags (e.g., including one or more flags listed above) identifyinggranular App Flow features. The App Flow capability may be sent in anICA init-response packet that is transmitted from the client 102 to theserver 106.

Referring to operation 4, the client 102 may provide VC-bind informationin the message (e.g., in the init-response for the WinStation Driver).The VC-bind information may include App Flow VC in WinStation DriverVC-bind structures. The VC-bind information may include informationassociating an identifier of a protocol (e.g., protocol name of a VCprotocol or ICA protocol) for communicating data using the insights VC,with an identifier of the insights VC or a component (e.g., WinStationDriver or VC module) of the client 102 or server 106. The VC-bindinformation may include, indicate or identify a protocol name to IDnumber binding (sometimes referred to as a protocol name to ID numberassociation). The protocol name may refer to or identify the core ICAprotocol or a protocol of the App Flow VC. The ID number may identify orrefer to at least one of: an associated VC module, the App Flow VC, orthe WinStation Driver. The client 102 (e.g., client-side agent 502, orWinStation Driver) may provide or assign the protocol name to ID numberbinding to an App Flow module that is responsible for implementing theApp Flow VC at the client 102. The VC module can be part of theWinStation Driver, or include the WinStation Driver, or may be separatefrom the WinStation Driver. The VC module can be part of the client-sideagent 502 (e.g., VDA), or include the client-side agent 502, or may beseparate from the client-side agent 502. The client may load the VCmodule to implement, initiate and/or establish the App Flow VC at theclient 102. The client may send or report the VC-bind information to theserver 106 in the same message (e.g., init-response packet or message)or another message (e.g., another init-response packet or message). TheVC-bind information may be sent on behalf of the WinStation Driverresponsible for implementing the core ICA protocol that supports the AppFlow VC and/or any other VCs. The server 106 can receive the VC-bindinformation (e.g., VC protocol name to ID number binding), and can usethe VC-bind information to access or otherwise open the App Flow VC andsend data on it. The VC-bind information can be used by any of thenetwork device(s) 604 in the network link 518 to find and parse out theApp Flow VC among other VCs and core protocol.

Referring to operation 5, the server 106 may commit capabilities for theApp Flow VC and/or the ICA/HDX session. The server 106 may receive amessage (e.g., init-response packet or message) from the client 102,which can include at least one of: the App Flow capability or theVC-bind information. The server can parse, extract, determine and/oranalyze the App Flow capability received from the client 102. Forexample, the server can detect, identify or determine the protocolversions and/or additional flags that might have been set by the clientand network device(s) in the App Flow capability.

The server 106 can compute or determine a Session protocol versionand/or Session protocol flag(s), for instance using or according toinformation set in the App Flow capability. For example, the Sessionprotocol version may be set to either 0 or the minimum value of theprotocol versions reported by all of the entities (e.g., server, networkdevice(s), client). The Session protocol version can be set to 0 if nonetwork device 604 between the client 102 and the server 106 supports it(e.g., supports the App Flow VC or feature), or if the client 102 doesnot support it (e.g., supports the App Flow VC or feature), or if theApp Flow VC itself is not reported by the client 102 in a protocol nameto ID number binding, and/or if there is neither protocol-levelencryption or custom App Flow VC-level encryption negotiated for thesession. If the value of the Session protocol version is 0, then no AppFlow VC is created or established for the session (e.g., ICA, RDP or HDXsession).

The server 106 can commit or finalize the Session protocol version(e.g., if this value is not 0) and/or the Session protocol flag(s) thatare computed or determined. The server 106 can communicate or propagatethe committed Session protocol version and/or the Session protocolflag(s) to all other entities (e.g., network device(s), client) byincluding these in an App Flow capability in a message (e.g., aninit-connect packet or message) sent from the server to the client. Allor some of these entities can read the committed Session protocolversion and/or Session protocol flag(s). This process can avoid creatingthe App Flow VC and/or sending App Flow data points (e.g., insights)unnecessarily if no network devices in the network link (between theclient 102 and the server 106) is present, interested in or capable ofprocessing the App Flow insights, and/or if the client-side agent 502does not support the App Flow feature, and/or if encryption (e.g.,protocol-level encryption, or custom App Flow VC encryption) is notnegotiated or present. For instance, and in some embodiments, thecapability exchange process described herein may also be used tonegotiate custom App Flow VC protocol-level encryption methods and keys,so that data sent over the App Flow VC can only be decrypted by adesignated network device or the client (e.g., that has access to thecustom App Flow VC protocol-level encryption methods and keys).

The server 106 can initiate, establish, create and/or open the App FlowVC, and can start inserting, writing, providing and/or sending variousinsights (e.g., events and data points) into the App Flow VC. The server106 can initiate, establish, create and/or open the App Flow VC, and/orprovide the insights, responsive to at least one of: determining thatthe Session protocol version is not 0, committing the Session protocolversion and/or the Session protocol flag(s), or sending the committedSession protocol version and/or the Session protocol flag(s) to theother entities. The server 106 can open or create the App Flow VC in thesession (e.g., HDX or ICA session), and can leave the protocol packetsof App Flow VC (and/or other VCs) uncompressed (e.g., in the top levelICA/HDX protocol), and can leave the protocol packets of App Flow VC(and/or other VCs) non-interleaved (e.g., to facilitate parsing by otherentities). The App Flow VC data stream can be compressed (e.g., at theApp Flow protocol level). The server 106 can provide session data (e.g.,in JSON format or protocol) from various stack or VC components, intocorresponding VCs, which may be implemented in user or kernel-mode. Thesession data can include insights that are directed into the App FlowVC. The App Flow VC can carry messages formed and sent in JSON format,to facilitate parsing by interested entities (e.g., network devices)and/or the client, and to ensure easy extensibility. For instance, thenetwork devices (e.g., gateway and/or SD-WAN devices) may be configuredto support and understand the JSON format. However, any other format canbe used, that for instance is supported by the entities and/or can beefficiently transmitted and processed.

The App Flow VC can communicate, transmit, carry or convey one or moreApp Flow messages (e.g., in JSON or other format). Each App Flowmessages may include at least one of:

-   -   Transport stack connection ID;    -   HDX Session Globally Unique Identifier (GUID) (facilitates        correlation of each individual data point with a user and        session environment);    -   Terminal Services Session ID;    -   context (additional context to allow other entities to correlate        data points);    -   timestamp; and    -   source (e.g. Virtual Channel or other system component        originating the data point).

In some embodiments, a message may include or contain at least one of:(a) Key (Name), (b) Type, or (c) Value. Messages may be categorized inat least three different groups/types:

i) Version: Such a message can be a first message (e.g., JSON message)sent over the App Flow VC from server to client. Such a message candenote the JSON protocol version, which may be different from the AppFlow VC protocol version. Such a message can be used to advertise theset of events and data points implemented by the server to otherentities. Similarly, such a message may be a first message (e.g., JSONmessage) sent over the App Flow VC from client to server, and can beused for a similar purpose.

ii) Event: Such a message can allow the server to signal the occurrenceof an event on the server. For example, the server may send an eventthat signals that “something happened” for a particular VC in a HDXsession, or indicate another system event. Similarly, such a message canbe used by the client to raise events with other entities.

iii) Key Value: Such a message can describe an individual single datapoint. For example, such a message can describe that a certain datapoint has this specific value for a virtual channel in an HDX session.

By way of illustration, events can include but is not limited to one ormore of the following:

Application launch, timestamp

Application termination, timestamp

Process termination, timestamp

Session disconnection/termination, timestamp

USB announce device

USB device accepted

USB device rejected

USB device gone

USB device reset

USB device reset endpoint

By way of illustration, data points can include but is not limited toone or more of the following:

Domain name

Logon ticket

Server name

Server version

Session type (e.g., desktop, application)

Client name

Client version

Client serial number

Application name

Application module path

Application process ID

Application launch time

Application termination time

Session termination time

Launch mechanism

Automatic reconnection/Session reliability mechanism

ICA Round Trip Time (RTT)

Layer 7 (L7) latency

VC bandwidth

Multi-stream ICA (MSI) stream type (primary or secondary)

Referring to operation 5′, the client 102 can read the sessioncapabilities, can open the App Flow VC, and can write data into the AppFlow VC. The client 102 may read the Session protocol version and/orSession protocol flag(s) committed by the server 106. According to theinstructions (e.g., the committed Session protocol version and Sessionprotocol flag(s)), the client 102 may access or open the App Flow VC.Similar to the server 106, the client 102 may send data points via theApp Flow VC in the client-to-server direction, to be retrieved by one ormore network devices and/or the server 106.

Referring to operation 6, a network device (e.g., gateway or SD-WANdevice) 604 may read or access the data (e.g., insights) from the AppFlow VC (e.g., data packet or data stream in the App Flow VC). Eachinterested or capable network device 604 may read the Session protocolversion and/or Session protocol flag(s) committed by the server 106. Asinstructed by the server 106 (e.g., via the committed Session protocolversion and/or Session protocol flag(s)), a respective network device604 may efficiently parse out (e.g., relative to deep parsing) the AppFlow VC among other VCs and core protocol (e.g., using the VC-bindinformation), and may read the insights (e.g., data points) carried inthe App Flow VC. The VC-bind information (e.g., VC protocol name to IDnumber association) may be useful to the network device 604 to detect,identify and/or parse out the App Flow VC among other VC protocols(e.g., VC-specific or VC-level protocols) and core (or top levelICA/HDX) protocol. The network device 604 may ignore all otherprotocol(s). This can be further facilitated by the fact that the AppFlow VC packets are uncompressed (e.g., at the top level protocol) andnon-interleaved. This can substantially improve the number of HDXsessions that may be supported by a network device 604 such as a gatewayor SD-WAN device. This also improves the user experience on HDXsessions, since a network device 604 is no longer a bottleneck forprocessing (e.g., deep parsing) and throughput. The network device 604may decrypt data points (e.g., at the App Flow VC protocol level) ifencryption had been negotiated. (See, e.g., test results discussedbelow.)

Referring to operation 7, the network device 604 can combine thereceived App Flow VC data with additional network analytics. The networkdevice 604 can combine the received App Flow VC data with additionalnetwork analytics generated, accessed and/or provided by the networkdevice 604, to form or produce combined insights. The network device 604can send the combined insights to a management tool or service 602(e.g., analytics service) for further analysis and/or presentation to anadministrator. For example, combined insights may be sent to CitrixDirector or Citrix Management and Analytics System (MAS) or athird-party Insights tools. Citrix MAS can correspond to or include acentralized network management and analytics system. From a singleplatform, administrators can view, manage network devices, andtroubleshoot network related issues, or issues with specific publisheddesktops and applications. In some embodiments, the management tool orservice (e.g., MAS) 602 may be configured as an App Flow collector on anetwork device (e.g., Citrix Gateway or Citrix SD-WAN) 604, throughwhich HDX/ICA traffic is flowing. The management tool or service (e.g.,MAS) 602 may receive the records (e.g., combined insights) from thenetwork device (e.g., Citrix Gateway or Citrix SD-WAN) 604, analyze therecords, and can present them (e.g., in HDX Insight administrator view).The presented data (e.g., in HDX Insights administrator view) may helpadministrators in troubleshooting issues related to latencies,bandwidth, desktop or application launch time, desktop or applicationresponse time, etc.

Referring to operation 8, the client-side agent 502 can read and candrop (e.g., ignore, remove, discard, filter away) the App Flow VC data.The client 102 may read some or all data points, and can drop some orall data points that the client 102 is not interested in. The client 102may parse, extract, read and/or interpret the data points (e.g.,provided by the server) from the App Flow VC. For example, the client102 may log information about the App Flow VC data, present informationto the end user, respond back to the server, etc. The client may decryptdata points if encryption had been negotiated.

Referring to operation 8′, the server-side agent 504 can read and candrop (e.g., ignore, remove, discard, filter away) App Flow VC data.Similar to the client 102, the server 106 may read and/or ignore some orall of the data points sent by the client 102. For instance, the server106 may parse, extract, read and/or interpret the data points (e.g.,provided by the client 102) from the App Flow VC. For example, theserver 106 may log, present information to the end user, respond back tothe client 102, etc. The server 106 may decrypt data points ifencryption had been negotiated.

In some embodiments, the client-side agent 502 (e.g., Workspace App) maysend some data points on the App Flow VC, which can be correlated withserver-side agent 504 (e.g., VDA) data points to provide more insightsinto an HDX Session. In certain embodiments, the server-side agent 504(e.g. VDA) may implement, add or insert data points with session orapp-specific details, e.g. URL's that may be accessed in the session,etc.

In some embodiments, one or more alternative methods of implementing theApp Flow VC may include: (a) Separating CGP connections from a networkdevice to the server-side agent (e.g. VDA); (b) Channeling data from theserver-side agent (e.g. VDA) to the monitoring tool/service (e.g.Director/MAS) over an independent transport layer connection; (c) Basedon uniquely identifying Connection ID/Session GUID exchanged over HDXprotocol, sending tagged data points from each entity (e.g., client-sideagent, network device, server-side agent) directly to a Cloud Service.Then the Cloud Service may correlate the data points from the differentsources based on a tag (Connection ID/Session GUID). This architectureis more appropriate to customers/organizations that are more willing toaccept the use of a Cloud Service as opposed to on-premisescustomer/organization owned/controlled network devices and services.

Cloud services can be used in accessing resources including networkapplications. Cloud services can include an enterprise mobilitytechnical architecture, which can include an access gateway in oneillustrative embodiment. The architecture can be used in abring-your-own-device (BYOD) environment for instance. The architecturecan enable a user of a client device (e.g., a mobile or other device) toboth access enterprise and personal resources from a client device, anduse the client device for personal use. The user may access suchenterprise resources or enterprise services via a client applicationexecuting on the client device. The user may access such enterpriseresources or enterprise services using a client device that is purchasedby the user or a client device that is provided by the enterprise touser. The user may utilize the client device for business use only orfor business and personal use. The client device may run an iOSoperating system, and Android operating system, or the like. Theenterprise may choose to implement policies to manage the client device.The policies may be implemented through a firewall or gateway in such away that the client device may be identified, secured or securityverified, and provided selective or full access to the enterpriseresources. The policies may be client device management policies, mobileapplication management policies, mobile data management policies, orsome combination of client device, application, and data managementpolicies. A client device that is managed through the application ofclient device management policies may be referred to as an enrolleddevice. The client device management policies can be applied via theclient application for instance.

In some embodiments, the operating system of the client device may beseparated into a managed partition and an unmanaged partition. Themanaged partition may have policies applied to it to secure theapplications running on and data stored in the managed partition. Theapplications running on the managed partition may be secureapplications. In other embodiments, all applications may execute inaccordance with a set of one or more policy files received separate fromthe application, and which define one or more security parameters,features, resource restrictions, and/or other access controls that areenforced by the client device management system when that application isexecuting on the device. By operating in accordance with theirrespective policy file(s), each application may be allowed or restrictedfrom communications with one or more other applications and/orresources, thereby creating a virtual partition. Thus, as used herein, apartition may refer to a physically partitioned portion of memory(physical partition), a logically partitioned portion of memory (logicalpartition), and/or a virtual partition created as a result ofenforcement of one or more policies and/or policy files across multipleapps as described herein (virtual partition). Stated differently, byenforcing policies on managed apps, those apps may be restricted to onlybe able to communicate with other managed apps and trusted enterpriseresources, thereby creating a virtual partition that is not accessibleby unmanaged apps and devices.

The secure applications may be email applications, web browsingapplications, software-as-a-service (SaaS) access applications, WindowsApplication access applications, and the like. The client applicationcan include a secure application launcher. The secure applications maybe secure native applications, secure remote applications executed bythe secure application launcher, virtualization applications executed bythe secure application launcher, and the like. The secure nativeapplications may be wrapped by a secure application wrapper. The secureapplication wrapper may include integrated policies that are executed onthe client device when the secure native application is executed on thedevice. The secure application wrapper may include meta-data that pointsthe secure native application running on the client device to theresources hosted at the enterprise that the secure native applicationmay require to complete the task requested upon execution of the securenative application. The secure remote applications executed by a secureapplication launcher may be executed within the secure applicationlauncher application. The virtualization applications executed by asecure application launcher may utilize resources on the client device,at the enterprise resources, and the like. The resources used on theclient device by the virtualization applications executed by a secureapplication launcher may include user interaction resources, processingresources, and the like. The user interaction resources may be used tocollect and transmit keyboard input, mouse input, camera input, tactileinput, audio input, visual input, gesture input, and the like. Theprocessing resources may be used to present a user interface, processdata received from the enterprise resources, and the like. The resourcesused at the enterprise resources by the virtualization applicationsexecuted by a secure application launcher may include user interfacegeneration resources, processing resources, and the like. The userinterface generation resources may be used to assemble a user interface,modify a user interface, refresh a user interface, and the like. Theprocessing resources may be used to create information, readinformation, update information, delete information, and the like. Forexample, the virtualization application may record user interactionsassociated with a graphical user interface (GUI) and communicate them toa server application where the server application may use the userinteraction data as an input to the application operating on the server.In this arrangement, an enterprise may elect to maintain the applicationon the server side as well as data, files, etc., associated with theapplication. While an enterprise may elect to “mobilize” someapplications in accordance with the principles herein by securing themfor deployment on the client device (e.g., via the client application),this arrangement may also be elected for certain applications. Forexample, while some applications may be secured for use on the clientdevice, others might not be prepared or appropriate for deployment onthe client device so the enterprise may elect to provide the mobile useraccess to the unprepared applications through virtualization techniques.As another example, the enterprise may have large complex applicationswith large and complex data sets (e.g., material resource planningapplications) where it would be very difficult, or otherwiseundesirable, to customize the application for the client device so theenterprise may elect to provide access to the application throughvirtualization techniques. As yet another example, the enterprise mayhave an application that maintains highly secured data (e.g., humanresources data, customer data, engineering data) that may be deemed bythe enterprise as too sensitive for even the secured mobile environmentso the enterprise may elect to use virtualization techniques to permitmobile access to such applications and data. An enterprise may elect toprovide both fully secured and fully functional applications on theclient device. The enterprise can use a client application, which caninclude a virtualization application, to allow access to applicationsthat are deemed more properly operated on the server side. In anembodiment, the virtualization application may store some data, files,etc., on the mobile phone in one of the secure storage locations. Anenterprise, for example, may elect to allow certain information to bestored on the phone while not permitting other information.

In connection with the virtualization application, as described herein,the client device may have a virtualization application that is designedto present GUIs and then record user interactions with the GUI. Thevirtualization application may communicate the user interactions to theserver side to be used by the server-side application as userinteractions with the application. In response, the application on theserver-side may transmit back to the client device a new GUI. Forexample, the new GUI may be a static page, a dynamic page, an animation,or the like, thereby providing access to remotely located resources.

The client device may use cloud services to connect to enterpriseresources and enterprise services at an enterprise, to the publicInternet, and the like. The client device may connect to enterpriseresources and enterprise services through virtual private networkconnections. The virtual private network connections, also referred toas microVPN or application-specific VPN, may be specific to particularapplications (e.g., as illustrated by microVPNs), particular devices,particular secured areas on the client device (e.g., as illustrated byO/S VPN), and the like. For example, each of the wrapped applications inthe secured area of the phone may access enterprise resources through anapplication specific VPN such that access to the VPN would be grantedbased on attributes associated with the application, possibly inconjunction with user or device attribute information. The virtualprivate network connections may carry Microsoft Exchange traffic,Microsoft Active Directory traffic, HyperText Transfer Protocol (HTTP)traffic, HyperText Transfer Protocol Secure (HTTPS) traffic, applicationmanagement traffic, and the like. The virtual private networkconnections may support and enable single-sign-on authenticationprocesses. The single-sign-on processes may allow a user to provide asingle set of authentication credentials, which are then verified by anauthentication service. The authentication service may then grant to theuser access to multiple enterprise resources, without requiring the userto provide authentication credentials to each individual enterpriseresource.

The virtual private network connections may be established and managedby an access gateway. The access gateway may include performanceenhancement features that manage, accelerate, and improve the deliveryof enterprise resources to the client device. The access gateway mayalso re-route traffic from the client device to the public Internet,enabling the client device to access publicly available and unsecuredapplications that run on the public Internet. The client device mayconnect to the access gateway via a transport network. The transportnetwork may use one or more transport protocols and may be a wirednetwork, wireless network, cloud network, local area network,metropolitan area network, wide area network, public network, privatenetwork, and the like.

The enterprise resources may include email servers, file sharingservers, SaaS/Web applications, Web application servers, Windowsapplication servers, and the like. Email servers may include Exchangeservers, Lotus Notes servers, and the like. File sharing servers mayinclude ShareFile servers, and the like. SaaS applications may includeSalesforce, and the like. Windows application servers may include anyapplication server that is built to provide applications that areintended to run on a local Windows operating system, and the like. Theenterprise resources may be premise-based resources, cloud basedresources, and the like. The enterprise resources may be accessed by theclient device directly or through the access gateway. The enterpriseresources may be accessed by the client device via a transport network.The transport network may be a wired network, wireless network, cloudnetwork, local area network, metropolitan area network, wide areanetwork, public network, private network, and the like.

Cloud services can include an access gateway and/or enterprise services.The enterprise services may include authentication services, threatdetection services, device manager services, file sharing services,policy manager services, social integration services, applicationcontroller services, and the like. Authentication services may includeuser authentication services, device authentication services,application authentication services, data authentication services andthe like. Authentication services may use certificates. The certificatesmay be stored on the client device, by the enterprise resources, and thelike. The certificates stored on the client device may be stored in anencrypted location on the client device, the certificate may betemporarily stored on the client device for use at the time ofauthentication, and the like. Threat detection services may includeintrusion detection services, unauthorized access attempt detectionservices, and the like. Unauthorized access attempt detection servicesmay include unauthorized attempts to access devices, applications, data,and the like. Device management services may include configuration,provisioning, security, support, monitoring, reporting, anddecommissioning services. File sharing services may include filemanagement services, file storage services, file collaboration services,and the like. Policy manager services may include device policy managerservices, application policy manager services, data policy managerservices, and the like. Social integration services may include contactintegration services, collaboration services, integration with socialnetworks such as Facebook, Twitter, and LinkedIn, and the like.Application controller services may include management services,provisioning services, deployment services, assignment services,revocation services, wrapping services, and the like.

The enterprise mobility technical architecture of cloud services mayinclude an application store. The application store may includeunwrapped applications, pre-wrapped applications, and the like.Applications may be populated in the application store from theapplication controller. The application store may be accessed by theclient device through the access gateway, through the public Internet,or the like. The application store may be provided with an intuitive andeasy to use User Interface.

Referring to FIG. 7, an example system that illustrates animplementation of App Flow 700 data points collection and transmissionat a server (or server-side agent or VDA) is depicted. The system caninclude a client-side agent 502 (e.g., Citrix Workspace App orReceiver), a server-side agent 504 (e.g., Citrix Virtual Apps andDesktops VDA), and a network device 604 (e.g., a NetScaler device). Inconnection with FIG. 7 for instance, NetScaler App Flow (NSAP) issometimes also referred to as App Flow. Citrix NetScaler (or NetScaler)is referenced here by way of example, and can also be replaced with anytype or form of network device. VDA is referenced here by way ofexample, and can also be replaced with any type or form of server-sideagent 504. Likewise, Citrix Workspace App (or Receiver) is referencedhere by way of example, and can also be replaced with any type or formof client-side agent 502. The following is an example process flow, andcan include some or all of the following operations:

At operation 705, after the VDA boots, the NSAP service on the VDA caninstantiate an Event Tracing for Windows (ETW) Controller and can startan ETW live session. At operation 710, the Citrix Workspace App canstart an ICA session and a new NSAP driver can initiate the NSAP VC fromthe Receiver endpoint. The NSAP driver may discard all data coming onthis NSAP VC, or it can use the statistics received. At operation 715 aand 715 b, user mode HDX components on the VDA can use the NSAP SDK(NsapSetxxx) to send data points to Citrix Netscaler App ExperienceService (CtxNsapSvc) 717. At operation 720, Kernel mode HDX componentson the VDA can use the NSAP SDK (NsapSetxxx) to send data points toCtxNsapSvc. At operation 725, a CtxNsap provider library can send ETWevents to the NSAP ETW Consumer 727 hosted by CtxNsapSvc. At operation730, the NSAP Service can encapsulate the data points (e.g., into a JSONformat) and can send it to the NSAP virtual channel (or App Flow VC). Atoperation 735, network device 604 (e.g., NetScaler) can intercept theNSAP VC message and can extract the required data. At operation 740, themessage can further be transmitted to the Citrix Workspace App alongwith all other HDX traffic. At operation 745, the Receiver NSAP VCdriver may discard the NSAP VC message. In testing mode, the NSAP VCdriver may parse the content and can display it in DebugView or in afile for test automation purposes. The NSAP VC driver may also interpretthe data in non-testing mode.

Referring to FIGS. 8-10, illustrative test results are providedincluding those from an implementation using an App Flow VC. The sessionbandwidth (BW) in each of FIGS. 8 and 9 can refer to HDX traffic load.FIG. 8 depicts a graph 800 of example test results on number of ICA/HDXsessions for a session bandwidth of 125 Kbps (e.g., typical workload).The test results, from left to right, show the case where no insightswere parsed (when no App Flow VC is implemented), the case wheredeep-parsing is performed (when no App Flow VC is implemented), and thecase where App Flow VC is implemented for efficient parsing. FIG. 9depicts a graph 900 of example test results on number of ICA/HDXsessions for a session bandwidth of 400 Kbps (e.g., graphics richworkload). The test results, from left to right, show the case where noinsights were parsed (when no App Flow VC is implemented), the casewhere deep-parsing is performed (when no App Flow VC is implemented),and the case where App Flow VC is implemented for efficient parsing. Foreach session bandwidth, the number of HDX sessions that can be served isabout 2.5× higher with the App Flow VC based implementation, as comparedwith the deep parsing implementation. The actual difference is likely tobe higher because of certain bottlenecks in the test setup. As discussedearlier, deep parsing is computationally and resource intensive, whichreduces the number of HDX sessions that can be served. Even when the AppFlow VC is used (and some computational resource is consumed for a moreefficient parsing), the number of HDX sessions that can be served appearto be similar to the case where no insights were parsed.

FIG. 10 depicts a graph 1000 of example test results on network deviceCPU usage (e.g., Gateway appliance packet engine CPU usage). The testresults show the case where no insights were parsed (when no App Flow VCis implemented), the case where deep-parsing is performed (when no AppFlow VC is implemented), and the case where App Flow VC is implementedfor efficient parsing. The CPU usage is shown under the condition thatthe number of sessions are maxed out. Sessions are considered maxed outwhen outgoing bandwidth goes down by 10% and user experience (UX)becomes sluggish. The test results show that when App Flow VC is used(and some computational resource is consumed for a more efficientparsing), the level of CPU usage (about 23%) is only slightly higherthan that for case where no insights were parsed (about 15%). Hence, CPUusage under the App Flow VC based implementation is fairly low even whennumber of sessions are maxed out. However, in the case wheredeep-parsing is performed, the CPU usage (which is near 100%) is muchhigher than both of the other cases.

Referring now to FIG. 11, depicted is a flow diagram of a method 1100 ofestablishing independent application flow virtual channels. The method1100 may be performed or implemented using any of the componentsdetailed herein, for example, the client 102, the server 106, theappliance 200, the network link 518, or the network device 604, amongothers. In brief overview, a first computing device may send a requestmessage for virtual channels (1105). The first computing device mayreceive a response message indicating capabilities (1110). The firstcomputing device may determine capabilities in supporting virtualchannels (1115). The first computing device may establish virtualchannels (1120). The first computing device may identify insights fromvirtual channel (1125).

In further detail, a first computing device (e.g., the client 102 or theserver 106) may send a request message for virtual channels (e.g.,virtual channels 506 a-n or 508 a-n) (1105). The request message may betransmitted, provided, or otherwise sent by the first computing deviceto a second computing device (e.g., the client 102 or the server 106),and may be communicated via an intermediary device (e.g., a networkdevice 604 in the network link 518). The request message may be arequest to setup or establish at least one virtual channel for anapplication flow feature (also referred to as an insights virtualchannel) of the first computing device or the second computing device,or the intermediary device. The first computing device may generate therequest message to indicate one or more capabilities of the firstcomputing device (and/or to request one or more capabilities of otherdevices) to support an insights virtual channel between the firstcomputing device and the second computing device. The capabilities mayindicate compatibility of the first computing device in supporting aninsights virtual channel, and may indicate types of insights datatransferrable via the virtual channel. In some embodiments, thecapabilities may include one or more protocol versions supportable bythe first computing device in using at least one of the virtual channelsto support insights. For example, the request message can indicate thehighest version or most recent version of the protocol supported by thefirst computing device in accordance to which the insights are to beprovided via the virtual channel.

The first computing device may receive a response message indicatingcapabilities (1110). The response message may be identified, obtained,or received by the first computing device from the second computingdevice, and may be communicated via the network device (e.g., throughthe network link 518). Upon receipt of the request message from thefirst computing device, the second computing device may generate theresponse message to include the one or more capabilities of the secondcomputing device to support an insights virtual channel between thefirst computing device and the second computing device. The capabilitiesmay indicate compatibility of the second computing device in supportingan insights virtual channel, and may indicate types of insights datatransferrable via the virtual channel. In some embodiments, thecapabilities may include one or more protocol versions supportable bythe second computing device in using at least one of the virtualchannels to support insights.

In some embodiments, the second computing device may generate theresponse message to include information for establishing the virtualchannel to support insights. The information may include: an identifierof a protocol (e.g., protocol type, protocol name, or ICA protocol) inaccordance to which data is to be communicated via the insights virtualchannel, an identifier of the virtual channel itself to be used as theinsights virtual channel, and a component (e.g., WinStation, VC module,or other application or communication interface) of the first computingdevice to use the insights virtual channel, among others. Theinformation may also include an association between the identifier ofthe protocol and the identifier of the virtual channel, or anassociation between the identifier of the protocol and the component ofthe first computing device (e.g., VC bind information). With thegeneration of the response message, the second computing device maytransmit the response message to the first computing device.

When transmitted from the second computing device, the intermediarydevice may identify, intercept, or otherwise receive the requestmessage. Upon receipt or interception, the intermediary device mayinsert the one or more capabilities of the intermediary device tosupport the insights virtual channel between the first computing deviceand the second computing device via the intermediary device. Thecapabilities may indicate compatibility of the intermediary device insupporting an insights virtual channel, and may indicate types ofinsights data transferrable via the virtual channel between the firstcomputing device and the second computing device. In some embodiments,the capabilities may include one or more protocol versions supportableby the intermediary device in using at least one of the virtual channelsto support insights. In some embodiments, the intermediary device mayinclude or insert information for establishing the virtual channel tosupport insights. The information inserted by the intermediary devicemay be the same as described above with respect to the second computingdevice. With the insertion of the capabilities or information, theintermediary device may forward or otherwise send the response messageto the first computing device.

The first computing device may determine capabilities in supportingvirtual channels (1115). Upon receipt of the response message, the firstcomputing device may parse the response message to identify thecapabilities of the second computing device and the network device insupporting an insights virtual channel. By parsing the response message,the first computing device may determine the capabilities in supportingthe insights virtual channel. From the response message, the firstcomputing device may identify the one or more protocol versionssupported by the second computing device and the intermediary device.Based on the identification, the first computing device may find,identify, or determine at least one protocol version for the insightsvirtual channel supported by the first computing device, the secondcomputing device, and the intermediary device. For example, the firstcomputing device may determine the highest or most recent protocolversion supported by all three devices. In addition, the first computingdevice may identify the information for establishing the insightsvirtual channel from the response message, such as the associationbetween the identifier of the protocol and the identifier of the virtualchannel or the association between the identifier of the protocol andthe component of the first computing device (e.g., VC bind information).

The first computing device may establish virtual channels (1120). A setof virtual channels may be established between the first computingdevice and the second computing device via the intermediary device. Insome embodiments, the virtual channels in the set may be interleavedwith each other to carry data between the first computing device and thesecond computing device. The data carried via the virtual channels maybe compressed. Separately from the set of virtual channels, the firstcomputing device may initiate, setup, or otherwise establish an insightsvirtual channel. The insights virtual channel may be separate from(e.g., not interleaved with) the other virtual channels between thefirst computing device and the second computing device. The insightsvirtual channel may carry uncompressed data relating to analyticsregarding the communications between the first computing device and thesecond computing device via the intermediary device. The insightsvirtual channel may be used by one or more of the three devices, such asthe first computing device, the second computing device, and the thirdcomputing device (e.g., an intermediary device or network device 604 inthe network link 518).

The establishment of the insights virtual channel may be in accordancewith the capabilities the first computing device, the second computingdevice, and the intermediary device. In some embodiments, the firstcomputing device may use at least one protocol version identified assupported by the first computing device, the second computing device,and the intermediary device to establish the insights virtual channel.For example, the first computing device may use the highest or mostrecent protocol version determined to be supported by all three devicesto establish the insights virtual channel. In some embodiments, thefirst computing device may generate and send the information onestablishment of the insights virtual channel to the second computingdevice and the intermediary device. The information may have beenlacking in the response message from the second computing device or theintermediary device, and may be generated by the first computing device.The information may include, for example, the association between theidentifier of the protocol and the identifier of the virtual channel orthe association between the identifier of the protocol and the componentof the first computing device (e.g., VC bind information). Oncegenerated, the first computing device may send the information via oneof the set of virtual channels previously established between the firstcomputing device and the second computing device.

The first computing device may identify insights from the insightsvirtual channel (1125). With the establishment of the insights virtualchannel, the first computing device may exchange analytics data(sometimes referred herein as insights or metrics) regarding the firstcomputing device, the second computing device, any other device(s),and/or the communication between the first computing device and thesecond computing device via the network link of the intermediary device.The analytics data may include events and data points, e.g., regardingthe communication session as described herein above. The analytics datamay be uncompressed and may be non-interleaved with other data, and maybe lacking in the other set of virtual channels established between thefirst computing device and the second computing device. To access, thefirst computing device may identify the insights virtual channel fromthe virtual channels using the setup information. The information mayinclude, for example, an identifier of the protocol, an identifier ofthe virtual channel, or the component of the first computing device touse the insights virtual channel, among others, or any association therebetween. Once the insights virtual channel is identified, the firstcomputing device may retrieve, identify, or otherwise access theanalytics data (e.g., from the second computing device or theintermediary device). In some embodiments, the first computing devicemay request, fetch, or otherwise retrieve the analytics data from thesecond computing device or the intermediary device. In some embodiments,upon establishment of the insights virtual channel, the first computingdevice, the second computing device, and the intermediary device all maycommence exchanging or sharing analytics data via the insights virtualchannel. Using the analytics data, the first computing device, thesecond computing device, or the intermediary device may re-configure,adjust, or set the data exchanged or shared via the other virtualchannels.

State Transition of App Flow Metrics During Network Appliance Failover(High-Availability)

Referring now to FIG. 12, depicted is a block diagram of a system 1200for transitioning application flow metrics during appliance failover.The system 1200 may include one or more components detailed herein inconjunction with FIGS. 5-11, such as the client 102, the client-sideagent 502, one or more network devices 604 a and 604 b (sometimesreferred herein as a gateway or an intermediary device), at least onevirtual channel 506 and 508, a server-side agent 504, and a server 106.In overview, a virtual channel (e.g., an insights virtual channel) maybe rerouted or redirected from one network device 604 b to anothernetwork device 604 a. For instance, one of the network devices 604 a or604 b (hereinafter generally referred to as network device 604) maydetermine whether to re-route a virtual channel from itself to anothernetwork device 604. In some embodiments, a client 102 or server 106 maydetect a failure or failover situation associated with a first networkdevice 604 b, and may determine whether to re-route a virtual channelthrough the first network device 604 b to another network device 604 a.The virtual channel 506 and 508 may have been established between theclient 102 and server 106 through the network device 604. The re-routingmay be performed in response to a network (application) failover. Inresponse to the determination, the network device 604 may identify orreceive a protocol state of the virtual channel. The protocol state mayinclude information regarding the establishment of the virtual channel,such as an association between the protocol identifier with theidentifier of the virtual channel or between the protocol identifierwith a component of the client 102 or server 106 (e.g., WinStation, VCmodule, or another application). Using the protocol state, the networkdevice 604 may access the insights exchanged across the insights virtualchannel 506 or 508. The insights may be from the client 102, the server106 or another network device, and may be communicated through thenetwork device 604.

State Transition Via Shared State

In some embodiments, and by way of a non-limiting example, a networkdevice (e.g., the network device 604 of system 1200) may beload-balanced, e.g., a Gateway may be load-balanced between Gatewayinstance 1 (e.g., network device 604 b) and Gateway instance 2 (e.g.,network device 604 a). A specific HDX session may be initiallyestablished from client 1 via Gateway 1 to VDA host 1. An App Flow VCmay have been established and data points may have been transmitted. ICAprotocol-level encryption may have been negotiated and used, e.g., Basicor Secure ICA encryption. App Flow VC-specific protocol-level encryptionmay have been negotiated and used. A failure of Gateway 1 (e.g., networkdevice 604 b) may cause the connection to be re-routed via Gateway 2(e.g., network device 604 a). In another scenario, a network disruptionmay cause client 1 to re-establish transport level connection, which inturn may re-route the connection via Gateway 2, even without any failureat Gateway 1. In both of these cases, the client 1 can reconnect to thehost HDX session (e.g., using standard CGP Session Reliabilitymechanism).

In transitioning the App Flow state from Gateway 1 to Gateway 2, therecan be a problem with continuing to re-interpret the protocol traffic,including decrypting ICA protocol-level encryption and/or App Flowprotocol-level encryption, and identifying App Flow VC messages.Protocol state maintained by Gateway 1 can be continuously saved inshared storage, or at a globally available service, or a RemoteDictionary Server (Redis), etc. The protocol state may include, but isnot limited to any one or more of the following: (a) App Flow VCnegotiated capabilities: Session protocol version and flags, protocolversion and flags for each entity; (b) App Flow VC protocol name to IDnumber association/binding; (c) Recorded App Flow VC version, events,data points; (d) Encryption method, keys, last encrypted byte at ICAprotocol-level; and/or (e) Encryption method, keys, last encrypted byteat App Flow VC protocol-level.

Gateway 2 may retrieve and restore the shared protocol state from sharedstorage, identified by protocol-level identifier such as CGP cookie,Session GUID, etc. To continue parsing App Flow VC messages, Gateway 2may for example perform any one or more of the following: (a)Re-synchronize transmitted and received packets at CGP-level; (b) Uselast encrypted byte (at ICA protocol-level) to continue to decrypt ICAtraffic and maintain encryption state; (c) Optionally, for optimization,use flags in CGP protocol to indicate presence of self-contained AppFlow VC message; (d) If Gateway 2 can support the same Sessioncapabilities as the already negotiated ones by Gateway 1: use lastencrypted byte (at App Flow VC protocol-level) to continue to decryptApp Flow VC messages and maintain encryption state. Otherwise: Do notsupport App Flow VC; or clear protocol state and trigger re-negotiationof App Flow VC protocol capabilities as previously described. This maycause delay in processing but can ensure that App Flow functionality isstill supported. Thus, the App Flow state can be successful transitionedfrom Gateway 1 to Gateway 2, and Gateway 2 can continue to receive andinterpret new events and data points.

State Transition Via in-Line State Re-Initialization

In some scenarios, the protocol state may not be easily, efficiently orquickly shared between different Gateway instances (e.g., the networkdevices 604 of system 1200). For example, for purposes ofhigh-availability and resiliency, redundant Gateway instances may resideon different cloud platforms, e.g., Microsoft Azure or Amazon AWS. Foradditional resiliency a redundant Gateway instance may exist in aco-location facility or on-premises. Therefore, as an alternative, theApp Flow channel (or VC) may be designed as stateless or, rather, duringfailover the new Gateway instance may be re-initialized (or re-seeded)with sufficient state to continue parsing the App Flow data, where there-initialization may be performed in-line via a tunneling protocol,e.g. CGP, or via the App Flow VC itself, or a combination. By way of anon-limiting example, the in-line state re-initialization process mayoccur as illustrated below:

A network device may be load-balanced, e.g., a Gateway may beload-balanced between Gateway instance 1 and Gateway instance 2. Aspecific HDX session may be initially established from client 1 viaGateway 1 to VDA host 1. An App Flow VC may have been established anddata points may have been transmitted. As a result of determining thatstrong network-level encryption, e.g. with TLS or DTLS existingend-to-end, ICA protocol-level encryption, e.g., Basic or Secure ICAencryption, may be turned off. App Flow VC-specific protocol-levelencryption may have been negotiated and used. A failure of Gateway 1 maycause the connection to be re-routed via Gateway 2. In another scenario,a network disruption may have caused client 1 to re-establish transport,which in turn might have re-routed the connection via Gateway 2, evenwithout any failure at Gateway 1. In both of these cases, the clientcould use the standard CGP Session Reliability mechanism to reconnect tothe host HDX session.

When transitioning the App Flow state from Gateway 1 to Gateway 2, therecan be a problem with continuing to re-interpret the protocol traffic,including App Flow protocol-level encryption, and identifying App FlowVC messages. In some embodiments, upon CGP reconnect, new CGP capabilityis exchanged. In client-to-host and/or host-to-client direction, the CGPcapability carries sufficient data to allow Gateway 2 to identify theApp Flow VC. This data can include the App Flow VC protocol name to IDnumber association/binding. Also upon CGP reconnect, the client and hostcan issue an event to their App Flow VC modules, which can instruct theApp Flow VC itself to for instance (re)send one or more of thefollowing: [1] App Flow VC negotiated capabilities: Session protocolversion and flags, protocol version and flags for each entity(Unencrypted. First data point sent); [2] Encryption method, keys, lastencrypted byte at App Flow VC protocol-level (Unencrypted); [3] App FlowVC JSON protocol version; [4] Session GUID; [5] Additional data pointsmay also be sent reflecting current HDX session state; and so on. Thebulk of historical data points that do not require real-timesynchronization could still be stored in a globally reachable orreplicated MAS.

To continue parsing App Flow VC messages, Gateway 2 may for exampleperform one or more of the following: (a) Re-synchronize transmitted andreceived packets at CGP-level; (b) Optionally, for optimization, useflags in CGP protocol to indicate presence of self-contained App Flow VCmessage; (c) Use the App Flow VC protocol name to ID numberassociation/binding to start parsing the App Flow VC; (d) If Gateway 2can support the same Session capabilities as the already negotiated onesby Gateway 1 (which can be a reasonable assumption for Cloud instanceswhere capabilities can be kept uniform): i) Queue all App Flow VCpackets, e.g. those previously CGP-buffered by client and/or host andnow re-synchronized by CGP, until packets with unencrypted data points[1] and [2] above are received, ii) Use last encrypted byte (at App FlowVC protocol-level) to continue to decrypt App Flow VC messages andmaintain encryption state, and iii) Interpret and flush the previouslyCGP-buffered data points, if any; (e) Otherwise (if Gateway 2 cannotsupport the same Session capabilities as the already negotiated ones byGateway 1): i) Do not support App Flow VC, or ii) clear protocol stateand trigger re-negotiation of App Flow VC protocol capabilities aspreviously described. This may cause delay in processing but can ensurethat App Flow functionality is still supported. Thus, the App Flow statecan be successful transitioned from Gateway 1 to Gateway 2, and Gateway2 continues to receive and interpret new events and data points.

State Transitions During Appliance Failover

Referring now to FIG. 13, depicted is a flow diagram of a method 1300 oftransitioning application flow metrics during appliance failover. Themethod 1300 may be performed or implemented using any of the componentsdetailed herein, for example, the client 102, the server 106, theappliance 200, or the network device 604 (or network device 604 a or 604b of system 1200), among others. The method 1300 can include thefunctionalities described herein, such as state transition via sharedstate and state transition via in-line state re-initialization. In briefoverview, a first intermediary device may determine whether a virtualchannel is re-routed (1305). If not re-routed, the first intermediarydevice may monitor the virtual channels (1310). If re-routed, the firstintermediary device may receive a protocol state (1315). The firstintermediary device may identify information and capabilities from theprotocol state (1320). The first intermediary device may perform a statetransition (1325). The first intermediary device may access insightscommunicated via a virtual channel (1330).

In further detail, a first intermediary device (e.g., the network device604 b) may determine whether an insights virtual channel (e.g., virtualchannel 506 or 508) (1305) is re-routed. The insights virtual channelmay be established between a first computing device (e.g., the client102 or the server 106) and a second computing device (e.g., the client102 or the server 106). Furthermore, the insights virtual channel mayhave been initially established through a second intermediary device(e.g., the network device 604 b) between the first computing device andthe second computing device. The insights virtual channel may bere-routed from the second intermediary device to the first intermediarydevice in response to a failure at or associated with the secondintermediary device. The failure causing the re-routing may include, forexample, a network disruption causing interruption of the insightsvirtual channel, disabling of the second intermediary device, or anyother event leading to the second intermediary device being unable orunsuitable to handle or carry the insights virtual channel between thefirst and second computing device. To determine whether the insightsvirtual channel is to be re-routed, the first intermediary device maymonitor the insights virtual channel for one or more failures at orassociated with the second intermediary device. Upon detection of thefailure, the first intermediary device may determine that the insightsvirtual channel is to be re-routed. Otherwise, if the insights virtualchannel is determined to be maintained or not re-routed, the firstintermediary device may monitor the virtual channels (1310). The firstintermediary device may continue to monitor for re-routing of theinsights virtual channel from another device (e.g., the secondintermediary device or another network device 604) to the firstintermediary device, and may repeat the functionality of (1305).

If the insights virtual channel is determined to be re-routed, the firstintermediary device may receive a protocol state (1315). The firstintermediary device may access, retrieve, or otherwise access theprotocol state of the insights virtual channel re-routed from the secondintermediary device to the first intermediary device. The protocol statemay be used to re-configure the insights virtual channel upon re-routingfrom one intermediary device to another intermediary device. In someembodiments, the first intermediary device may retrieve, identify, orotherwise receive the protocol state from the first computing device orthe second computing device, between which the insights virtual channelwas established. The protocol state may be received from a component(e.g., App Flow VC module, WinStation, or other application) of thefirst computing device or the second computing device.

In some embodiments, the first computing device may identify theprotocol state from another source, besides the first computing device,the second computing device, or the second intermediary device. Theprotocol state for the insights virtual channel may be stored andmaintained on a shared storage (e.g., a database in the network link518). The shared storage may be accessible by one or more intermediarydevices. For example, when the second intermediary device establishedthe insights virtual channel between the first and the second computingdevices, the second intermediary device may have stored the protocolstate for the insights virtual channel onto the shared storage. Thefirst intermediary device may access the storage to retrieve, obtain, orotherwise identify the protocol state maintained thereon.

In some embodiments, the first intermediary device may use aprotocol-level identifier to identify the protocol state. Theprotocol-level identifier may describe the communications through theinsights virtual channel, such as a cookie or a session identifier. Thefirst intermediary device may identify the protocol-level identifierfrom the insights virtual channel (e.g., based on the communications) tobe re-routed from the second to the first intermediary device. The firstintermediary device may also identify the protocol-level identifier fromthe shared storage accessible by one or more of the intermediarydevices. With the identification, the first intermediary device may findor identify the protocol state of the insights virtual channel beingre-routed in the shared database.

The first intermediary device may identify information and capabilitiesfrom the protocol state (1320). From the protocol state for the insightsvirtual channel, the first intermediary device may extract, obtain, orotherwise identify the information or capabilities, among other data.The protocol state may include information and capabilities in relationto the insights virtual channel. The first intermediary device mayidentify the information included in the protocol state. The informationof the protocol state may be for the establishment or re-establishmentof the insights virtual channel between the first computing device andthe second computing device. The information may include: an identifierof a protocol (e.g., protocol type, protocol name, or ICA protocol) inaccordance to which data is to be communicated via the insights virtualchannel, an identifier of the virtual channel itself to be used as theinsights virtual channel, and a component (e.g., WinStation driver, VCmodule, or other application or communication interface) of the first orthe second computing device to use the insights virtual channel, amongothers. The information may also include an association between theidentifier of the protocol and the identifier of the virtual channel oran association between the identifier of the protocol and the componentof the first computing device (e.g., VC bind information), among others.

The first intermediary device may determine or identify the capabilitiesincluded in the protocol state. The capabilities may indicate thecompatibility common among the first computing device, the secondcomputing device, and the second intermediary device in supportingcommunications of analytics data across the insights virtual channel.The capabilities of the protocol state may be negotiated across thefirst computing device, the second computing devices, and one of theintermediary devices (e.g., the second intermediary device) to supportcommunicating analytics data via the insights virtual channel. Theinsights virtual channel initially routed through the secondintermediary device may be establish in accordance with negotiationsacross the first computing device, the second computing device, and thesecond intermediary device. The negotiations may include identifying thehighest or most recent protocol version in accordance to which to setupthe insights virtual channel in communicating the insights. Thecapabilities identified from the protocol state may include one or moreprotocol versions supportable by the first computing device, the secondcomputing device, and the second intermediary device in using at leastone of the virtual channels to support insights.

In some embodiments, the first intermediary device may identify ordetermine other data included in the protocol state. The protocol statefor the insights virtual channel may also include data regarding theinsights virtual channel itself or communications through the insightsvirtual channel, such as a protocol name, information about one or moreevents, and data points, among others. The protocol name may define orinclude an identifier corresponding to a type of protocol used toestablish the insights virtual channel (e.g., ICA protocol). Theinformation on the events may correspond to a function or an action bythe first computing device or the second computing device, such as by anapplication or process running thereon. The data points may define ordescribe one or more events of one or more of the computing device(s)and the intermediary device(s), that can be communicated across theinsights virtual channel. The protocol state for the insights virtualchannel may also include data defining or supporting encryption of thecommunications across the insight virtual channel, such as an encryptionmethod, an encryption key, and one of the encrypted bytes, among others.The encryption method may define a cryptographic technique or protocolused to encrypt or obfuscate the analytics data (e.g., the events anddata points). The encryption key may define a transformation applied bythe encryption method in obfuscating the analytics data. The encryptedbyte may correspond to a chunk of the analytics data (in byte size)exchanged via the insights virtual channel. In some embodiments, theencrypted byte referred to in the protocol state may correspond to thelast encrypted byte transmitted across the insights virtual channelprior to re-routing from the second intermediary device to the firstintermediary device.

The first intermediary device may perform a state transition (1325). Inre-routing the insights virtual channel from the second intermediarydevice, the first intermediary device may perform the state transitionin accordance with a shared state or in-line state re-initializationtechnique as detailed herein. In some embodiments, the firstintermediary device may re-synchronize packets transmitted or receivedvia the insights virtual channel at a common gateway protocol level inperforming the state transition. The common gateway protocol level maybe defined by or may correspond to the protocol-level identifier. Usingthe gateway protocol level, the first intermediary device may determinea proper sequence of packets to synchronize the packets exchanged acrossthe insights virtual channel. In some embodiments, the firstintermediary device may initialize or re-initialize itself using atunneling protocol to perform the state transition. The tunnelingprotocol may be performed using, for example, a common gateway protocol(CGP) or via an App Flow virtual channel itself.

In some embodiments, the first intermediary device may negotiate withthe first computing device and the second computing device tore-establish the insights virtual channel from the second intermediarydevice to the first intermediary device itself. The negotiation mayinclude determination of the highest or most recent protocol versionsupported by all three devices in communicating the analytics data viathe insights virtual channel. Upon negotiation, the first intermediarydevice may establish the insights virtual channel between the first andthe second computing device through itself. With the re-establishment,the first intermediary device may use the encryption method, key, andbyte information (e.g., the last byte) to decrypt the analytics datapreviously exchanged across the insights virtual channel through thesecond intermediary device. By decrypting, the first intermediary devicemay identify or determine the last portion (e.g., the last byte) of theanalytics data exchanged through the previous insights virtual channel.From the last portion, the first intermediary device may commenceexchanging of the analytics data via the insights virtual channelbetween the first and second computing devices.

The first intermediary device may access insights communicated via theinsights virtual channel (1330). Using the received protocol state, thefirst intermediary device may retrieve, identify, or otherwise accessanalytics data (sometimes referred herein as insights) exchanged acrossthe insights virtual channel. In some embodiments, the firstintermediary device may initiate accessing of the analytics data inresponse to performance of the state transition. The analytics data maybe generated or may originate from the first computing device or thesecond computing device, and may include events and data pointsregarding the communication session as described herein above. The firstintermediary device may identify the insights virtual channel from a setof virtual channels established between the first and the secondcomputing device using the information. As discussed above, theinformation may include, for example, the association between theidentifier of the protocol and the identifier of the virtual channel orbetween the identifier of the protocol and the component of the firstcomputing device. With the identification of the insights virtualchannel, the first intermediary device may identify, retrieve, orotherwise access the analytics data exchanged between the firstcomputing device and the second computing device. In some embodiments,the first intermediary device may use the encryption method, key, orbyte information of the protocol state to decrypt the analytics dataexchanged through the insights virtual channel. The analytics data mayhave been encrypted prior to transmission by the first or the secondcomputing device. By decrypting, the first intermediary device mayrecover the original analytics data.

Efficient Identification and Prioritization of Multi-Stream ICA (MSI)HDX Streams

In multi-stream ICA (MSI), virtual channels may run on different MSIstreams with priority 0-3. The streams with different priority canimpart quality of service for the QoS for the virtual channels. InMulti-port ICA, separate ports have to be configured on the server-sideagent 504 (e.g. VDA). A network device, referenced here as SD-WAN by wayof illustration, can support MSI without multiple ports (e.g., using asingle port) by deep parsing CGP and ICA. In this manner, the SD-WAN canperform cross-session caching and compression, thereby offloadingreduction in consumption of ICA bandwidth and printing imagecompression, among other functionalities, via the data streams.

Referring now to FIG. 14, depicted is a block diagram of an examplerepresentation of MSI using a client-side network device 604 a and aserver-side network device 604 b. In system 1400, although there can beany number of streams 1405 (e.g., MSI streams), the embodiment shown anddiscussed herein provides for 4 MSI streams by way of illustration: 1primary stream, which handles the core ICA protocol and some VCs, and 3secondary streams, which handle additional VCs. In some embodiments, AppFlow VC messages are sent on the primary MSI stream, so a network devicecan parse only the primary stream to access insights from these messagesin the App Flow VC. App Flow VC messages can also be sent on any otherpre-determined MSI stream, as long as the network device can know ordetermine which stream to access the insights. To enable identificationof the separate streams, their type and priority, stream-identifyingdata points can be initially sent on all MSI streams, e.g. the oneprimary MSI stream and three secondary MSI streams, as soon as eachstream is created for instance. The stream-identifying data points caninclude at least one of, but may not be limited to: (a) Session GUID;(b) Stream ID; (c) Priority; or (d) Stream type: Primary vs. Secondary.For example, a network device (e.g., a Citrix SD-WAN) can use thepriority to prioritize HDX traffic accordingly.

During the lifetime of an HDX session, the priority of individual VCsmay change and they may be re-assigned to different streams. This has noimpact on the App Flow processing, since the App Flow VC may always beprocessed on a predetermined (e.g., primary) stream. However, thepriority of individual streams may also change, in which casestream-identifying data points may be sent again to indicate the changeof priority. In some embodiments, a VC write operation may normally sendthe data point only on the dedicated stream associated with a VC, e.g.the primary stream in case of the App Flow VC. But in the case of an AppFlow implementation, a modified VC write operation can be used to sendeach stream-identifying data point on the respective stream, to enable anetwork device to identify the separate streams, their type and currentpriority.

Referring now to FIG. 15, depicted is a flow diagram of a method 1500 ofprioritizing data streams for virtual channels. The method 1500 may beperformed or implemented using any of the components detailed herein,for example, the client 102, the server 106, the appliance 200, or thenetwork device 604 (e.g., the network devices 604 a or 604 b of thesystem 1400), among others. In brief overview, a first intermediarydevice may establish data streams comprising virtual channels (1505).The first intermediary device may determine an identifier for each datastream (1510). The first intermediary device may determine a priorityfor each data stream (1515). The first intermediary device may send theinformation on priority in data streams (1520). In some embodiments, thefunctionalities of (1505)-(1520) may be performed by the server 106 orthe server-side agent 504 (e.g., VDA).

In further detail, a first intermediary device (e.g., the network device604 a or 604 b) may establish a set of data streams (e.g., data streams1405) each comprising one or more virtual channels (e.g., virtualchannels 508 or 506) (1505). Each data stream may include one or morevirtual channels established between the first intermediary device and asecond intermediary device (e.g., the network device 604 a or 604 b).One of the data streams may include an insights virtual channel toexchange analytics data between the first intermediary device and thesecond intermediary device. The establishment of the data streamsincluding virtual channels may be in accordance to any of the techniquesdescribed herein in conjunction with FIGS. 5-14. The data stream maycommunicate data used to present a graphical user interface of anapplication hosted on one computing device (e.g., the server 106) on adisplay of a recipient computing device (e.g., the client 102). The datamay be communicated via the data stream in accordance with acommunications protocol, such as a multi-stream ICA protocol or a remotedesktop protocol, among others. Upon establishment, the firstintermediary device may transmit, receive, or otherwise communicate datafrom the sets of data streams to one of the computing devices (e.g.,client 102 or the server 106). The data from the data streams may becommunicated from the first intermediary device via a single port of thecomputing device.

The first intermediary device may determine an identifier for each datastream (1510). The first intermediary device may associate, assign, orotherwise determine the identifier of each data stream among the set ofdata streams established between the first computing device itself andthe second computing device. The identifier for a data stream mayuniquely reference one data stream, as distinguished from the other datastreams in the set established between the first intermediary device andthe second intermediary device. The identifier for the data stream maybe, for example, a globally unique identifier for a session (e.g., thecommunication session supporting the set of data streams) or a streamidentifier, among others. The identifier may be a numeric value or a setof alphanumeric strings, among others. In determining the identifier,the first intermediary device may create or generate the numeric valueor the set of alphanumeric strings. Upon generation, the firstintermediary device may associate or assign the identifier to thecorresponding data stream. In some embodiments, the first intermediarydevice may determine the identifier in establishing the correspondingdata stream between the first and second intermediary devices.

The first intermediary device may determine a priority for each datastream (1515). The first intermediary device may associate, assign, orotherwise determine the priority of each data stream among the set ofdata streams established between the first intermediary device itselfand the second intermediary device. The priority of each data stream maydefine a level of precedence, importance, urgency and/or quality ofservice of the data stream among the set of data streams incommunicating data between the first intermediary device and the secondintermediary device. For example, data to be sent via data stream of ahigher priority may be sent prior to data to be sent via another datastream of a lower priority. In some embodiments, to assign the priority,the first intermediary device may identify a type of each data stream.In some embodiments, in identifying the type of the data stream, thefirst intermediary device may specify, identify or determine a type ofdata communicated (or to be communicated) via the data stream. The datatransmitted via the data stream including the virtual channels mayinclude analytics data, audio, graphics, printer data, disk data, andmetadata, among others.

Based on the type of data (e.g., to be supported or transmitted), thefirst intermediary device may classify, identify, specify and/ordetermine the type of data stream. Each virtual channel included in adata stream may be configured and/or dedicated to delivering aparticular type of data. The first intermediary device may determineand/or specify the priority for each data stream (including the datastream with the insights virtual channel), corresponding to the type ofthe data stream. The determination/specification of priority may be inaccordance with a listing of priorities for types of data streams and/ortype(s) of virtual channels that may be carried in each type of datastream. For example, the listing may specify that the data streamcarrying analytics or voice data (e.g., via an analytics or voice VC) isto have a higher priority than the data stream delivering printer data.In some embodiments, the first intermediary device may determine atleast one of the data streams as a primary data stream and at least oneother of the data streams as a secondary data stream. Data streamsassigned as primary may be defined as taking precedent or priority overdata streams assigned as secondary.

The first intermediary device may send information in data streams(1520). The first intermediary device may transmit, provide, orotherwise send the information regarding the identifier and priority foreach data stream through the respective data stream. For example, thefirst intermediary device may send the identifier and priority for adata stream in the data stream itself (e.g., in an insights VC or otherVC of the data stream). The first intermediary device may send theidentifier and priority in a VC that is uncompressed and/ornon-interleaved with other VC(s) in the data stream. The information maybe accessed by another computing device (e.g., an SD-WAN, a gateway, oranother device in the network link 518) between the first intermediarydevice and the second intermediary device. In some embodiments, thefirst intermediary device may commence sending the information over thedata stream, upon establishment between the first and secondintermediary devices. The information sent via the corresponding datastream may include the identifier for the data stream, such as theglobally unique identifier for the session or the stream identifier,among others. The information sent in the respective data stream mayinclude the priority for the data stream, such as: the level ofprecedence/priority, the type of data stream, the type of data to beexchanged/communicated via the data stream, and/or the definition of thedata stream as primary or secondary, among others.

Subsequent to sending the information through the corresponding datastreams, the first intermediary device may detect, identify, orotherwise determine an update to the information for at least one of thedata streams. The determination may be repeated using thefunctionalities described above in (1510) and (1515). The update to theinformation for the data stream may lead to a change to the identifieror the priority, or both. For example, the change to the identifier mayinclude an updated globally unique identifier for the session or anupdated stream identifier, among others. The change to the priority mayinclude, for example, an updated level of precedence/priority, the newtype of data stream, the new type of data to be exchanged via the datastream, and/or the new definition of the data stream, among others. Upondetermining an update to the information, the first intermediary devicemay send the new information regarding the identifier and the priorityfor the data stream via the corresponding data stream. The sending ofthe new information may be performed in the same manner as thefunctionality in (1520). In this manner, the sending of information viathe data stream may be performed through a single port, without relianceon multiple ports by deep parsing CGP and ICA while providingcompression and cross-session caching of data transmitted.

L7 Latency Calculation and Communication Independent of Server (Host)Processing Time

In some embodiments, ICA/HDX protocol determines Round Trip Time (RTT)using measurement semantics that are different from a level 7 (L7)latency measurement. The ICA/HDX RRT use semantics that are gearedtowards user experience (UX) or application response time. The ICA RTTcalculation is based on a server's response to a client's query. Theserver's response is sent on the next outgoing packet. However, if anapplication does not perform an update, e.g., a desktop application isidle, there is no other server-to-client traffic. Hence, the nextoutgoing packet could be indefinitely delayed, resulting in ameasurement that may not be useful.

An App Flow VC monitoring network device (such as NetScaler Gateway orSD-WAN) may also be interested in reporting the end-to-end networklatency at Layer 7 of the OSI model between the monitoring networkdevice and the server (e.g., HDX host). This can be an important oruseful data point which reflects the network conditions between themonitoring network device and the server, and can also be combined withadditional measurements of the network conditions between the end-pointand the monitoring appliance for instance. In some embodiments, thenetwork device can calculate the L7 latency accurately by measuring thetime taken for a token, referred to as NsRTT (e.g., NetScaler Round TripToken) leaving the network device and returning back. The carrierchannel that brings back the NsRTT from the server includes ServerProcessing Time (SPT), which can be deducted from the total time, toobtain the actual “network device to server” L7 latency.

Calculating the SPT accurately can be very intricate by virtue of thecomplex modules and systems involved. One novel aspect lies in the waythe system propagates information (timestamp) between the discretesystem components and then assimilates it back. As illustrated in FIG.16, in the sequence 1600, the network device 604 can receive a packet,such as an ICA packet in an ICA stream (1605) from the receiver (e.g.,the client-side agent 502). The network device 604 can take a timestampT1 (1610) and insert a NsRTT token in the packet (e.g., in the ICApacket in the ICA stream) to the server (1615). The server-sideWinStation Driver 1202 (sometimes referred to as WDICA) can receive theNsRTT token, can take a timestamp T2 (1620), can record it (e.g., in theWindows Event, using Event Tracing for Windows (ETW) for instance), andcan fire an event (1625) (e.g., one or more functions specified by theinitial packet to be performed), which then goes into the Windows OSqueue and later gets delivered to the Citrix App Flow Service(CtxNsapSvc), for processing (1630). The time it takes for the ETW toreach CtxNsapSvc can be indeterministic.

The CtxNsapSvc, after receiving the ETW, can generate or construct apayload (e.g., JSON payload), and can dispatch or transmit it in an AppFlow packet for instance (1635). The payload can include the T2timestamp previously communicated via the event. Then, the WDICA, whichis at a lower layer of the ICA stack and essentially one layer above thenetwork transport module, can recalibrate, adjust, provide and/or updatethe SPT content in the JSON payload by calculating the true SPT (T3−T2),where T3 is a current timestamp taken by WDICA (e.g., the server-sideWinStation Driver 1602) upon receiving the payload or App Flow packet(1640). The WDICA can write the true SPT in a field of the payload(e.g., JSON payload), and can transmit the packet to the network device(1645). The network device 604, responsive to receiving the payload inthe packet, can take timestamp T4 and measure the true L7 latency usingthe SPT. The true L7 latency is equal to T4−T1−(T3−T2) (1650). Thenetwork device 604 can send an NSAP packet to the receiver (1655), andthe receiver can discard the packets (1660).

Referring now to FIG. 17, depicted is a flow diagram of a method 1700 ofcalculating latency in application layer (L7) communications independentof host server processing time. The method 1700 may be performed orimplemented using any of the components detailed herein, for example,the client 102, the server 106, the appliance 200, or the network device604, among others. In brief overview, a device may receive a packet(1705). The device may incorporate a token (e.g., flag, bit pattern,indicator, cookie) into the packet at time T1 (1710). The device maycause a duration D relative to time T2 (1715). The device may receive asecond packet at T3 (1720). The device may determine whether the packetincludes an identifier, e.g., of the device (1725). If the identifier isincluded, the device may determine a round-trip network time (1730).Otherwise, if the identifier is not included, the device may bypass thedetermination of the round-trip network time (1735).

In further detail, a device (e.g., the network device 604 or anotherdevice in the network link 518) may receive a first packet (1705). Thedevice may identify, intercept, or receive the first packet from anothercomputing device (e.g., the client 102). The first packet may begenerated in accordance with an application level protocol (L7), such asa remote desktop protocol (RDP), ICA protocol, and HDX protocol, amongothers. The first packet may include a header or a payload (sometimesreferred herein as a body) in accordance with the application levelprotocol. In some embodiments, the payload may include a script inaccordance with any language, such as Extensible Markup Language (XML),JavaScript, or JavaScript Object Notation (JSON), among others.Furthermore, the first packet may be destined to a recipient (e.g., theserver 106) as specified by one of the headers in the first packet. Insome embodiments, the first packet may correspond to a request by theclient to calculate the round-trip network time. Prior to forwarding,the device may update or modify the first packet to facilitate incalculation of round-trip network time.

The device may incorporate a token into the first packet at time T1(1710). Upon receipt of the first packet, the device may generate thetoken (sometimes referred herein as a roundtrip token) to include,insert, or otherwise incorporate into the first packet. The token may beor include a numeric value or a set of alphanumeric characters, and mayindicate that the recipient device is to facilitate in the calculationof the round-trip network time between the device and recipient. In someembodiments, the device may embed, add, or insert the token into aportion of the first packet, such as the header and the payload. In someembodiments, the device may also insert, include, or otherwiseincorporate at least one identifier (e.g., an entity identifier bit inan App Flow capability) into the first packet upon receipt from theother computing device. The identifier may be or include a numeric valueor a set of alphanumeric characters, and may be used to uniquelyreference the first packet in traveling through network (e.g., thenetwork link 518) to the recipient device and back to the device. Upongeneration, the device may embed, add, or insert the identifier into aportion of the first packet, such as the header or the payload. Inincorporating the token (and the identifier), the device may identify orotherwise record a time T1 at which the first packet is transmitted tothe server.

The device may cause a server to determine a duration D relative to timeT2 (1715). In sending the first packet to the server, the device maytrigger or cause the server or a driver running on the server (e.g., thedriver 1602) to receive the token. With receipt of the first packet fromthe device, the server may identify or record a time T2 at which thefirst packet is received by the server. In some embodiments, uponreceipt of the first packet, the server may parse the first packet toextract, obtain, or identify the token from the payload. With theidentification of the token, the server may commence determination ofthe duration D relative to time T2. The duration D may measure orcorrespond to an amount of time that the server consumes in handling orprocessing the first packet (e.g., the remainder of the payload in thefirst packet). In some embodiments, the server may maintain a timer tocount or keep track of the duration D.

In response to the first packet, the server may generate a second tokento send back to the device. By handling the first packet, the server maycause an application (e.g., App Flow Service or another program) hostedon the server to process the first packet. Based on the received firstpacket, the application may generate a payload to include the secondtoken. Similar to the first packet, the second packet may be generatedin accordance with an application level protocol (L7), such as a remotedesktop protocol (RDP), ICA protocol, and HDX protocol, among others.The second packet may include a header or a payload in accordance withthe application level protocol. In some embodiments, the payload of thesecond packet may include a script or information in accordance with anylanguage, such as Extensible Markup Language (XML), JavaScript, orJavaScript Object Notation (JSON), among others. Upon generation of thepayload, the application may output, send, or otherwise provide thepayload to the driver on the server. The driver in turn may insert,include, or otherwise incorporate the payload into the second packet.

While the second token is generated, the server may use the timer tokeep track of the duration D in generating the second token. Uponcompletion of the generation of the second packet, the server mayidentify the time counted on the timer as the duration D for generationof the second token. In some embodiments, the server may also use thetimer to keep track of time T2 a at which the driver is provided withthe payload from the application running on the server. Once identified,the server may determine the duration D based on the times T2 a and T2(D=T2 a−T2). With the determination, the server may include, insert, orotherwise incorporate the duration D into the second packet. In someembodiments, the server may embed, add, or insert the duration D (or T2a and/or T2) into the portion of the second packet, such as in theheader or the payload. In some embodiments, the server may insert,include, or otherwise incorporate the same identifier from the firstpacket into the second packet, such as in the header or the payload.Upon incorporation, the server may provide, transmit, or send the secondpacket with the duration D to the server.

The device may receive the second packet at T3 (1720). Subsequent to thetransmission, the device may receive the second packet from the server.A set of virtual channels (e.g., virtual channels 506 and 508) may havebeen established between the client and the server through the device.At least one of the virtual channels may be an insights virtual channelto exchange analytics data between the client and the server. Theinsights virtual channel may be separate from the other virtual channelsand may be non-interleaved with the other virtual channels. Thecommunications exchanged via the insights virtual channel may beuncompressed. The device may receive the second packet via the insightsvirtual channel from the server. In some embodiments, the header and thepayload of the second packet may also be uncompressed. Upon receipt ofthe second packet, the device may record, determine or identify time T3at which the second packet was received by the device.

The device may determine whether the second packet includes anidentifier (1725). The identifier (e.g., in an entity ID bit or field)may be incorporated into the first packet by the device and into thesecond packet by the server to reference the packet traveling to theserver and back to the device. To determine this, the device may parsethe second packet (e.g., in the payload) to extract, find, or identifythe identifier. When the identifier is found in the second packet, thedevice may determine that second packet includes the identifier. On theother hand, when the identifier is not found in the second packet, thedevice may determine that the second packet does not include theidentifier.

If the identifier is included (e.g., indicating that the second packetincludes information intended for the device), the device may determinea round-trip network time (sometimes referred herein as the true L7latency) (1730). The device may determine the round-trip network time inaccordance with time T3, T1, and D (or T2 a and T2). For example, thedevice may calculate the round-trip network time as the difference ofall three times, T3−T1−D. With the determination, the device may recordthe round-trip network time for the first packet. In some embodiments,the device may include, insert, or incorporate the round-trip networktime into the second packet, such as in the header or the payload.Otherwise, if the identifier is not included, the device may bypass thedetermination of the round-trip network time (1735). The device mayforego the calculation of the round-trip network time. In any event, thedevice may forward the second packet to the client device. In someembodiments, the device may discard the second packet received from thedevice. In some embodiments, the device may identify the round-tripnetwork trip (if inserted), prior to discarding.

L7 Latency Calculation and Communication Between Multiple NetworkDevices

The App Flow VC capability described in connection with FIGS. 15 and 16may be extended to include an additional field, where each entity(network device or client) may set a previously unused bit as the AppFlow VC capability travels from the server to the client (e.g., in anICA init-request packet). The bit (or field) can be used to uniquelyidentify each entity. Each entity can record the bit it uses as anEntity ID bit, and can set it in the App Flow VC capability so that itdoes not get used by other downstream entities.

When a network device inserts an NsRTT token in the ICA stream, thenetwork device can also update or decorate the token with itscorresponding Entity ID bit. As the NsRTT token travels in theclient-to-server direction, the NsRTT token may also be reused by othernetwork devices in the path by each adding/setting its correspondingEntity ID bit.

The SPT computation and the creation of L7 latency App Flow data pointat the server can proceed as described above, except that the server caninsert the combined Entity ID bits in the L7 latency App Flow datapoint. Each network device in the path can interpret the L7 latency AppFlow data point as described above, except that the network device canignore the data point unless it has its specific assigned Entity ID bitset.

Various elements, which are described herein in the context of one ormore embodiments, may be provided separately or in any suitablesub-combination. For example, the processes described herein may beimplemented in hardware, software, or a combination thereof. Further,the processes described herein are not limited to the specificembodiments described. For example, the processes described herein arenot limited to the specific processing order described herein and,rather, process blocks may be re-ordered, combined, removed, orperformed in parallel or in serial, as necessary, to achieve the resultsset forth herein.

It should be understood that the systems described above may providemultiple ones of any or each of those components and these componentsmay be provided on either a standalone machine or, in some embodiments,on multiple machines in a distributed system. The systems and methodsdescribed above may be implemented as a method, apparatus or article ofmanufacture using programming and/or engineering techniques to producesoftware, firmware, hardware, or any combination thereof. In addition,the systems and methods described above may be provided as one or morecomputer-readable programs embodied on or in one or more articles ofmanufacture. The term “article of manufacture” as used herein isintended to encompass code or logic accessible from and embedded in oneor more computer-readable devices, firmware, programmable logic, memorydevices (e.g., EEPROMs, ROMs, PROMs, RAMs, SRAMs, etc.), hardware (e.g.,integrated circuit chip, Field Programmable Gate Array (FPGA),Application Specific Integrated Circuit (ASIC), etc.), electronicdevices, a computer readable non-volatile storage unit (e.g., CD-ROM,USB Flash memory, hard disk drive, etc.). The article of manufacture maybe accessible from a file server providing access to thecomputer-readable programs via a network transmission line, wirelesstransmission media, signals propagating through space, radio waves,infrared signals, etc. The article of manufacture may be a flash memorycard or a magnetic tape. The article of manufacture includes hardwarelogic as well as software or programmable code embedded in a computerreadable medium that is executed by a processor. In general, thecomputer-readable programs may be implemented in any programminglanguage, such as LISP, PERL, C, C++, C #, PROLOG, or in any byte codelanguage such as JAVA. The software programs may be stored on or in oneor more articles of manufacture as object code.

While various embodiments of the methods and systems have beendescribed, these embodiments are illustrative and in no way limit thescope of the described methods or systems. Those having skill in therelevant art can effect changes to form and details of the describedmethods and systems without departing from the broadest scope of thedescribed methods and systems. Thus, the scope of the methods andsystems described herein should not be limited by any of theillustrative embodiments and should be defined in accordance with theaccompanying claims and their equivalents.

It will be further understood that various changes in the details,materials, and arrangements of the parts that have been described andillustrated herein may be made by those skilled in the art withoutdeparting from the scope of the following claims.

What is claimed is:
 1. A method, comprising: establishing, by a firstdevice, a plurality of data streams between the first device and asecond device, each of the data streams comprising at least one virtualchannel (VC), wherein a first data stream of the plurality of datastreams includes an insights VC; determining, by the first device foreach corresponding data stream of the plurality of data streams, anidentifier and a priority of the corresponding data stream; and sending,by the first device for each corresponding data stream of the pluralityof data streams, information regarding the identifier and the priorityof the corresponding data stream, in the corresponding data stream, tobe accessed by a computing device intermediary between the first deviceand the second device.
 2. The method of claim 1, further comprisingsending, in the corresponding data stream, the information including aglobally unique identifier of a session of the plurality of datastreams.
 3. The method of claim 1, further comprising sending, in thecorresponding data stream, the information including a type of thecorresponding data stream.
 4. The method of claim 3, wherein the type ofthe corresponding data stream corresponds to a primary data stream or asecondary data stream.
 5. The method of claim 1, further comprising:determining, by the first device for each corresponding data stream ofthe plurality of data streams, an updated priority of the correspondingdata stream; and sending, by the first device for each correspondingdata stream of the plurality of data streams, information regarding theidentifier and the updated priority of the corresponding data stream, inthe corresponding data stream.
 6. The method of claim 1, furthercomprising communicating, by the first device, data in the plurality ofdata streams via a single port to server or a client device.
 7. Themethod of claim 1, further comprising sending the information responsiveto establishing one of the plurality of data streams.
 8. A first device,comprising: at least one processor configured to: establish a pluralityof data streams between the first device and a second device, each ofthe data streams comprising at least one virtual channel (VC), wherein afirst data stream of the plurality of data streams includes an insightsVC; determine, for each corresponding data stream of the plurality ofdata streams, an identifier and a priority of the corresponding datastream; and send, for each corresponding data stream of the plurality ofdata streams, information regarding the identifier and the priority ofthe corresponding data stream, in the corresponding data stream, to beaccessed by a computing device intermediary between the first device andthe second device.
 9. The first device of claim 8, further comprisingsending, in the corresponding data stream, the information including aglobally unique identifier of a session of the plurality of datastreams.
 10. The first device of claim 8, further comprising sending, inthe corresponding data stream, the information including a type of thecorresponding data stream.
 11. The first device of claim 10, wherein thetype of the corresponding data stream corresponds to a primary datastream or a secondary data stream.
 12. The first device of claim 8,further comprising: determining, by the first device for eachcorresponding data stream of the plurality of data streams, an updatedpriority of the corresponding data stream; and sending, by the firstdevice for each corresponding data stream of the plurality of datastreams, information regarding the identifier and the updated priorityof the corresponding data stream, in the corresponding data stream. 12.The first device of claim 8, further comprising communicating, by thefirst device, data in the plurality of data streams via a single port toserver or a client device.
 14. The first device of claim 8, furthercomprising sending the information responsive to establishing one of theplurality of data streams.
 15. A non-transitory computer readable mediumstoring program instructions for causing one or more processors in afirst device to: establish a plurality of data streams between the firstdevice and a second device, each of the data streams comprising at leastone virtual channel (VC), wherein a first data stream of the pluralityof data streams includes an insights VC; determine, for eachcorresponding data stream of the plurality of data streams, anidentifier and a priority of the corresponding data stream; and send,for each corresponding data stream of the plurality of data streams,information regarding the identifier and the priority of thecorresponding data stream, in the corresponding data stream, to beaccessed by a computing device intermediary between the first device andthe second device.
 16. The non-transitory computer readable medium ofclaim 15, wherein the program instructions further cause the one or moreprocessors to: send, in the corresponding data stream, the informationincluding a globally unique identifier of a session of the plurality ofdata streams.
 17. The non-transitory computer readable medium of claim15, wherein the program instructions further cause the one or moreprocessors to: send, in the corresponding data stream, the informationincluding a type of the corresponding data stream.
 18. Thenon-transitory computer readable medium of claim 17, wherein the type ofthe corresponding data stream corresponds to a primary data stream or asecondary data stream.
 19. The non-transitory computer readable mediumof claim 15, wherein the program instructions further cause the one ormore processors to: determine, for each corresponding data stream of theplurality of data streams, an updated priority of the corresponding datastream; and send, for each corresponding data stream of the plurality ofdata streams, information regarding the identifier and the updatedpriority of the corresponding data stream, in the corresponding datastream.
 20. The non-transitory computer readable medium of claim 15,wherein the program instructions further cause the one or moreprocessors to: communicate data in the plurality of data streams via asingle port to server or a client device.